On this shore just after midnight on 7th December, 1941,
Japanese troops invaded the British colony of Malaya.
The Pacific War had begun.
Two hours later, Japanese planes, launched from aircraft carriers,
blew up the American fleet at Pearl Harbour.
A date which will live in infamy.
Within ten weeks came Japan's crowning victory,
the fall of Singapore,
symbol of British power in the east.
They were blows inflicted by the most devastating
combination of naval and air power ever seen.
Disaster had struck Britain and America.
But behind Japan's conquests lies an extraordinary secret
that has remained hidden for 70 years.
It's from Churchill. "I regard the attached as most serious.
"Here are all these Englishmen,
"two of them I know personally,
"collecting information and sending it to the Japanese."
It may seem incredible but it was the British who gave Japan
the know-how to take out Pearl Harbour
and capture Singapore.
Most shocking of all, for nearly two decades
the Japanese had infiltrated the very heart
of the British establishment.
The duty you owe is to this country,
not for any other country.
Through a mole who was a peer of the realm
known to Churchill himself.
In 1918, it felt as though the sun would never set
on the British Empire.
Britain was the dominant power in Asia,
and victorious after the First World War,
she didn't just rule the waves,
but the skies above them.
That year, she found a revolutionary way
of harnessing power from air and sea.
The first aircraft carrier was born...
HMS Argus.
These great ships could carry an entire squadron of planes
thousands of miles over the ocean
to bring them within range of anywhere on the planet.
Naval airpower
already is seen as something with great potential
and the British are recognised as being ahead.
One nation had particularly noticed the advantage the carriers
were giving the British.
Though it's largely forgotten today,
Japan had been an ally of Britain throughout the First World War.
It was a bond forged of two island peoples
who shared a maritime destiny.
When HMS Argus's sister ship the Eagle was launched in 1918,
the Japanese approached the Royal Navy
to inspect its state-of-the-art carrier,
yet surprisingly, they were rebuffed not once...
but ten times.
The Admiralty were very sensitive
about the technology around naval airpower.
They understood that this was a war-winning weapon
and indeed they described this as a deadly technology.
But the Air Ministry and the Foreign Office
saw the prospect of lucrative arms contracts with Japan.
So a compromise was agreed.
A civilian mission would be allowed to go to Japan
to help develop aircraft carriers
and encourage the Japanese to buy British military hardware.
Many thought that even with the new technology
Japan could never be a threat.
There was some now seemingly ridiculous stories
that the Japanese would never make good pilots
because they weren't good cavalrymen.
So you could sell them the aircraft
and they'd ever actually pose a threat to anyone.
It was believed the Japanese would want only gentlemen on the mission.
Whitehall believed they'd found the perfect man to lead it.
William Forbes-Sempill.
He was the son of a Scottish peer
and carried the title Master of Sempill.
His father has been an aide to George V.
Sempill himself goes to Eton.
He's one of the founder members of the Royal Flying Corps.
He transfers to the Royal Naval Air Service in 1916.
By 1917, aged 24,
he's a wing commander
and probably one of the most experienced British officers
in terms of naval airpower.
In 1920, the Sempill Mission left for Japan.
The Japanese get a hand-picked team of people,
the best people who developed this technology.
They're being shown what sort of aircraft they need...
..what sort of weapons they're being trained in,
both level-flight bombing and also the use of torpedoes.
This is a large-scale operation.
But these planes had limited range.
To take on an enemy on the other side of the Pacific Ocean,
the Japanese needed aircraft carriers.
This was way beyond their know-how.
The crucial technology is the deck.
The Japanese won't even attempt to construct the deck on the carrier
without British assistance.
Work began on the first Japanese carrier,
the Hosho.
Within two years, Sempill and his military missionaries
had given Japan's Naval Air Service
a potentially worldwide reach.
Sempill returned home.
The mission and its base were put under the vice command
of Yamamoto Isoroku,
the future mastermind of the attack on America's naval fortress,
Pearl Harbour.
The United States viewed Japan's growing naval strength
in the Pacific with increasing alarm.
At the Washington Conference of 1922,
the United States insisted on curbs to new Japanese warship building.
And crucially, the Anglo-Japanese alliance was terminated.
The price of the Washington Conference...
Britain's to abandon her cherished ally.
Japan is cut adrift.
What this means is the end really
of any discussions over naval technology or tactics.
All of that is going to come to an end.
This should have meant the severing of close military contact
between Britain and Japan.
But for another distinguished British naval flyer,
it was only the beginning.
By 1923, the aircraft carrier Hosho was in ocean-going service.
Now the Japanese needed training on how to operate its planes at sea.
They were in luck.
Britain's finest carrier pilot came calling.
Frederick Joseph Rutland, the son of a labourer,
had risen through the ranks to become squadron leader of the Eagle.
In a statement to British intelligence two decades later,
Rutland would explain his initial motive.
I felt that there were not going to be any more wars anyway.
I therefore decided to leave the service.
I have a strong instinct of adventure
and I decided to go to Japan.
Rutland, rather like Sempill, was a pioneering Royal Flying Corps pilot.
He joins in 1914.
He's an ace.
Rutland is famous for having spotted the German fleet
during the First World War,
hence his nickname, Rutland of Jutland.
And indeed, he's given one of the highest awards for this,
the Albert Medal.
At first, the Japanese put Rutland to work designing aircraft
chassis for the Japanese air force.
In Japan, my cover was the Mitsubishi company
in whose Tokyo building I had an office.
The Mitsubishi company was in fact the Japanese government.
Mitsubishi would later manufacture the Zero Fighter,
a plane that would cost the lives of thousands of Allied servicemen.
Rutland's paymasters then revealed
they had a much more important job for him.
They would increase his salary if he agreed to show their pilots
how to fly off and onto the decks of carriers.
They were so pleased with the results,
they gave him a year's leave on full pay.
The Sempill Mission and the information provided by Rutland,
certainly in the early to mid-1920s,
that is the foundation for the establishment
of the Japanese air arm.
During their respective periods in Japan, Rutland and Sempill
had formed a bond with their hosts they did not want to break.
Sempill, and indeed Rutland, develop an affinity with the Japanese.
Sempill's been in Japan for a long time.
He's made those personal connections.
It's not just friendship,
he's part of a revolutionary element almost within the Royal Navy.
He's part of this elite of air-power enthusiasts
and he's found kindred spirits.
Back in Britain, Sempill was carving out a new career,
but it was a role closely regulated by the Official Secrets Act.
His job seems to be going round advising governments
on arms sales, particularly of aircraft.
He should be very careful with any contacts he has.
If he's involved in discussions about technology transfer...
then he really ought to be letting the Government know.
But here at the National Archives in London,
recently declassified documents reveal that instead
Sempill was embarking on a far more dangerous path.
What we've got here is an MI5 report
and what's fascinating is it shows
the really forensic detail which MI5 was collecting on Sempill.
MI5's suspicions were first aroused in early 1923.
Several small incidents have recently shown that the Japanese
may be adopting other-than-orthodox methods for finding information
about the Royal Air Force.
Notably, your recent report that Colonel Sempill's servant
is a Japanese Naval Rating.
MI5 began an investigation of Sempill.
It turned out he wasn't just socialising with the Japanese,
he was in regular contact of a very different nature
with Japan's naval attache in London, Captain Toyoda.
Toyoda's not just a naval attache.
He's not just attending cocktail parties.
MI5 have evidence that he's also conducting his own espionage.
This is a trained intelligence officer,
not just a routine naval attache.
In February 1924, MI5 intercepted a letter from Sempill to Toyoda
which instantly raised the alarm.
You will remember I wrote to you on 7th January regarding large bombs.
The MI5 case officer noted...
Letter was enclosed in a double envelope,
the inner marked strictly confidential.
Air ministry were of the opinion that the matter referred
to a very confidential matter
re. new construction of bombs for the RAF.
This is about naval air power.
This is about destroying capital ships.
The Japanese are struggling to see how you can take out
major battleships with the relatively light aircraft of the 1920s.
It's this kind of forensic detail
that really persuades MI5 to take the next stage
which is to start to monitor Sempill's phone.
Phone-tapping was a new
and revolutionary surveillance in the 1920s.
It was also not sanctioned lightly.
The evidence that Sempill was trading Britain's secrets
to Japan began to mount.
13th May, 1924. Letter from Toyoda to Sempill
thanking him for the enclosed drawings
and detailed specifications...
..the perusal of which has afforded me great interest.
I am forwarding these papers to Japan for my home authority...
Sempill told Toyoda...
It would be useless for you to attempt to obtain
such information officially.
Sempill was passing on a whole range of secret information.
Enquiries showed that experiments with regard to
sound detectors for anti-aircraft work...
Toyoda write to Sempill saying he would be grateful
for any new information regarding parachutes,
the new Handley-Page and other machines.
In July 1924, Toyoda was invited to the British Fleet Review,
a public event.
Sempill used this opportunity to introduce his Japanese friends
to top British carrier designer, Sir Tennyson d'Eyncourt.
He wrote to Toyoda...
27th July, 1924.
I hope you have had a good look at the carriers.
D'Eyncourt will, with careful handling, produce much valuable data.
D'Eyncourt was warned off by the authorities.
Sempill then tried to procure another key figure for the Japanese,
Air Vice Marshal Sir Charles Vyvyan.
My dear commander, in my humble opinion,
the advice and active co-operation of such a man would be invaluable.
It is vital that this matter be kept quiet,
as should any word get out, it will cause trouble.
What Sempill is doing here is he's talent-spotting for Toyoda.
And of course, he's always anxious to keep this secret.
MI5 was appalled by Sempill's behaviour.
30th October, 1924.
Sempill's conduct in inciting Toyoda to endeavour to secure
Air Vice Marshal Vyvyan's services and to keep it dark
shows that he is quite unscrupulous
as regards what confidential British Air Force information
he passes on to the Japanese.
MI5 was unequivocal about Sempill's conduct.
He presented himself as a man only helping British companies
sell abroad.
Is Sempill a spy?
I'm not entirely sure.
Erm... I think...
he's interested in trying to portray himself
as a very useful conduit to naval technology.
I'm happier with the expression
he's pushing the envelope as far as it goes.
It's not illegal to talk to a foreign power
about military matters and military technology
if that information is a matter of open source.
But if it's information that's on the secret list,
yes, it's illegal. You're breaking the Official Secrets Act.
In July 1924, MI5 obtained evidence which they believe showed
that Sempill had clearly crossed the line into illegality.
Sempill had written to Toyoda with key technical details
about Britain's latest aero engine.
My dear commander,
it appears that the Jaguar IV has passed all the practical tests
imposed by landing on and flying off.
A feature of supreme importance that it exhibits
is the phenomenal slow-running, 100 to 150 rpm.
And he's talking about the Jaguar IV engine
which is one of the latest aero engines.
It's on the secret list.
If the information contained in this letter is in any way correct,
it would appear that Sempill has committed a serious infringement
of the Official Secrets Act.
MI5 believed it now had overwhelming evidence
that Sempill was spying for the Japanese.
Yet nothing was done about it.
MI5 don't want to give away sources and methods.
They're also, in the 1920s, reading telegrams
which are being passed by cipher from the Japanese embassy back to Tokyo.
And above all, this is the work of the antecedents of Bletchley Park.
They do not want to give that away.
That is one of the most closely guarded secrets of the British state.
So all this is potentially in jeopardy
if you bring a case against Sempill.
Despite the secrecy of MI5's operation,
one letter to Toyoda shows that Sempill
may have realised he was under suspicion.
10th December, 1924.
My dear commander, I meant to tell you today,
please be very careful how you use any information you get
and don't couple the name of any individual with it.
I will tell you more when we meet again
but I know just exactly how the wind blows
and the need for being super cautious.
In late October 1925,
Sempill travelled to Brough in Yorkshire
to visit the Blackburn Aircraft Factory.
This trip would later be of great significance.
His ostensible reason was to see a single-engine plane,
but his real motive was to spy on a new state-of-the-art flying boat,
the Iris,
Blackburn was building exclusively and secretly for the Air Ministry.
MI5 noted...
30th October, 1925.
Following on Sempill's visit to Brough,
the Blackburn Aeroplane Company forwarded to Sempill a letter
containing a detailed account of the performance of fleet aircraft
including the secret flying boat, the Iris,
in practically the same form as that requested by Toyoda.
6th January, 1926.
It is quite clear that not only is Sempill furnishing the Japanese
with aviation intelligence...
..but that he is being paid for doing so.
So this is the smoking gun provided by British code-breakers.
Essentially, this document is saying that Sempill is not just
providing information to friends but he's being paid for the gathering
of what they call aviation intelligence.
So it's paid espionage.
Then in early 1926,
the authorities were finally given the chance to challenge Sempill
without giving MI5's game away.
He was negotiating with the Greek government
to organise and train its Naval Air Service.
But the Greek naval attache in London reported to his government
a chilling warning about Sempill he'd received from the Air Ministry.
They do not think he is a proper man,
as what he would sell to us,
he may sell to any other state.
And I was told by the Air Ministry that he's in financial difficulties.
Sempill heard about the warning.
On 26th April, he wrote to the head of the Air Ministry
demanding a meeting about the cloud of suspicion which he claimed
hung over him and was damaging his business prospects.
MI5 now at last saw a way of confronting Sempill
without admitting they'd been intercepting his letters
and tapping his phone.
At 12 noon on 4th May, 1926,
in the office of the Deputy Chief of Air Staff,
Sempill's interrogation began.
Also present were Major Ball of Air Intelligence Security MI5
and the Director of Public Prosecutions himself,
Sir Archibald Bodkin.
The verbatim transcript was locked away for more than eight decades.
From the intercepts, the interrogators already knew
what Sempill had done.
The only question was, would he come clean?
In order that we may clear up this matter,
you will tell us what foreign governments
you've had activities with.
I've had connections of kind with most foreign governments.
As you know, I went out to take charge of the Japanese air service.
And since my return, I've had connections with the Chileans,
Greeks, Brazilians et cetera.
However, the connections I have had are really very small.
These connections do not amount to much.
Just a letter or two and perhaps a conversation here or there.
Sempill was instantly on dangerous ground.
His interrogators knew from the surveillance
that his dealings with the Japanese
had been anything but "really very small".
The transcript records how they began to probe that connection.
What is the nature of your relations with them?
Only on a friendly basis.
- Do they write? - Yes.
Do you reserve a salary?
No.
Who is the naval attache?
Captain Toyoda is the Japanese naval attache.
Do you receive applications from the Japanese or from any other power
which might be of a secret character?
If I ever have received any applications for information
and they're doubtful as to the secrecy or otherwise,
they mention it.
Is it left to them to say if it is secret?
I expect if I had all the correspondence
I could produce letters from the Japanese attache
asking for information,
saying that it may be something of the nature of secret.
If he wants a parachute or bombs or anything,
he represents the matter to his chief and the chief takes the action.
Sometimes Captain Toyoda refers to me.
You mentioned that you might receive a request about parachutes or bombs.
Did they ask you about parachutes or bombs?
This is not in my line.
The real truth was that the very first MI5 intercept had shown
Sempill giving away secret information about bombs.
You will remember I wrote to you
on the 7th January regarding large bombs.
MI5 had also obtained evidence that Sempill was being paid regularly
by the Japanese.
Sempill's initial claim had been he had only helped them
out of good will.
So they expect you to do this as an act of friendship?
I told them when I left Japan that I would.
And they're casting a good deal of work on you.
Yes. They do bother me to a certain extent.
I have helped
but simply because I believe it for the best to help.
I should be considerably out-of-pocket.
The money I have received from the Japanese
would not carry one very far.
Have you had any remuneration from the Japanese?
Yes, small presents.
They write to thank me for the great help I've given them,
said they did not know what to do about it.
They gave me £100 last Christmas time.
Is that the only occasion they've been so generous?
Every Christmas, I receive their thanks.
If I weighed up all I have done, it would be worth more than £100.
The interrogators now moved to the heart of the matter...
The Japanese attache's motive for dealing with Sempill
rather than directly with the Air Ministry.
What is the object of the Japanese asking for information
which they could have got for nothing
on application to the Air Ministry?
They could come here and ask any question they like.
I can't say exactly as to the motives
as to whether they go to the Air Ministry or not.
But they know that I know their situation.
They have faith in my knowledge and experience and recommendations
and rely on me.
You did not think that they'd come here first
and find that they cannot get information
- and then write to Colonel Sempill about it? - I cannot say.
This is the danger of such an arrangement. Of course,
with all of your knowledge and experience in general,
you would know the answer to many questions they might not
be able to get from here.
Yes, no doubt.
You see the danger of such an arrangement?
Yes.
The obvious danger is that if there is an anybody who knows such things
which are kept secret, they may let the cat out of the bag.
You are your own judge on these matters.
Have you ever referred any question to the Air Ministry as to whether
you should answer this question
or that question by another foreign power?
No. I don't think there's any case of that kind.
Because the detailed evidence of Sempill's dealings
with the Japanese had been established by covert methods,
it could not be used against him.
But the interrogators had an ace up their sleeves.
While on the train to visit the Blackburn factory in Brough
the previous November,
Sempill had made a foolish mistake.
He'd talked openly to foreign air attaches, one of them from Chile,
about the secret aircraft the British were developing.
A witness to this conversation reported it to MI5.
He heard the Master of Sempill discussing in the presence
of two attaches of foreign powers,
the futility of the Air Ministry's policy of secrecy
regarding certain aircraft.
Incidentally, he referred to the Iris as one of the aircraft
on the secret list in question.
Sempill's loose talk provided the one piece of damning evidence
obtained openly that could be used against him.
You might take it from me that it is perfectly plain
that on your way up to Brough,
the Iris was mentioned to the Chilean representative.
As far as I can recollect,
I said that a large flying boat was being constructed by Blackburn.
- And that was the sort of show day to see a single-engine seaplane? - Yes.
Why did you want to see the Iris?
You'd previously acknowledged it was on the secret list.
Naturally, being interested particularly
in the marine side of aviation
and knowing the officer extremely well who was designing this machine,
who was at one time under me, I was anxious to see it.
Well, why not ask the Air Ministry
if they had any objection to you getting these particulars?
It would have been the wisest and most patriotic thing to do.
I admit in that case it would have been the thing to have done.
With this admission,
Sempill had effectively confessed
to a breach of the Official Secrets Act.
Do I understand that neither the Japanese nor any other power
ever asked for you other than general questions?
Did they ask about the Iris?
No.
But of the Japanese had requested information about the Iris.
He was lying.
There is such a thing as a law in this country.
- Have you read the Act of 1920? - No.
You should take my advice and see a solicitor,
acquaint yourself with the spirit of the Act.
You're a sort of law unto yourself.
The public law of the country is entirely disregarded.
The fault was, in a sense, double.
Firstly, you had no right to obtain that information.
And secondly, you induced somebody at those works
- to give you that information. - I do not dispute that.
The duty you owe is to this country,
not for any other country.
The Director of Public Prosecutions concluded with a prophetic warning.
We have got, I believe,
a paramount position in regards to air matters.
If information we have found in details
are in any way communicated to a foreign power,
we, in effect, are providing the material
by which that foreign power can become a more effective enemy.
Despite this, at a high-powered meeting in Whitehall on 13 May 1926,
chaired by the Foreign Secretary himself, Sir Austen Chamberlain,
it was decided not to prosecute Semple.
He'd been let off the hook,
though the Director of Public Prosecutions wrote
that he could not free his mind
of the uneasiness he felt about the case.
He's a member of the aristocracy,
you wouldn't want to necessarily see this come to trial.
If he carries on, well, that might be a different matter.
MI5 know that even if they hold this trial in camera,
Semple will know what's going on
and he will blow the whistle on MI5 sources
and they can't afford to do that.
Re-examination of the files has uncovered another worrying dimension to Semple's activities
which went far beyond the shores of Great Britain.
This is a letter from Semple to Commander Toyoda.
He says, My dear Commander,
I hear that one Hunter who was with me in Japan as a WO2,
that's a Warrant Officer 2,
is now in the American Air Service at Honolulu.
He does not know much and is a rather weak character
but they may try and use him.
Do what you like, but I suggest you keep an eye on him.
Yours sincerely, WS Semple.
This is extraordinary because this is essentially
Semple assisting the Japanese with counter-espionage
and they're telling the Japanese that their people in Honolulu
need to keep an eye on him.
Honolulu is of course Hawaii, it's Pearl Harbour,
so we can see where all this is pointing.
By 1930, the help of men like Semple and Rutland
meant that Pearl Harbour was now a viable Japanese target.
They had achieved astonishing advances.
In just seven years, Japan had developed a carrier fleet
equal in size and strength to the Royal Navy.
Japan now have the means to realise her imperial ambitions.
She set her sights on Southeast Asia.
The ultimate prize was Singapore.
It lay at the foot of the British colony of Malaya
and was her strategic linchpin for the whole region.
Back in 1920, under the Anglo-Japanese alliance,
a grateful Britain had granted Japan naval concessions
in Penang at the northern end of the peninsula.
Japanese warships could dock at the port
and easily observe British defences.
Japanese businessmen began buying up prime sites
from Penang all the way to Singapore.
They overlooked the area where the British ships would be grouping,
where there might be a future development of the harbour.
There was almost a pattern of purchase going on.
Japan's interest was not just commercial.
She needed people on the ground
to gather intelligence for a future invasion.
What you're seeing in the 1930s, to some extent,
is a Japanese diaspora across Southeast Asia.
The Japanese are providing a lot of, if you like, new services.
Photographers, engineers, a whole set of traditional services.
Under the front of these businesses,
Japanese intelligence began inserting sleeper agents
from Penang to Singapore.
The identity of one would be revealed
after Japan's victories 10 years later.
He was identified as the barber in Singapore
cutting the British and Australian hair.
What happened? He turned out he was a colonel in the Japanese army.
You know, when you go into a barber's
they start talking and that, they get all sorts of information.
The sheer number of Japanese citizens,
which was in thousands, made blanket surveillance practically impossible.
To make matters even worse, the British found it difficult
to distinguish between Chinese and Japanese residents.
Singapore's melting pot was the perfect hiding place for spies.
They're acquiring the workaday, routine intelligence
that you would require to invade Southeast Asia -
The width of bridges, numbers of troops,
weaknesses of air defences, locations of logistical stores and arms dumps.
Like MI5 in London, British intelligence in the Far East
was expert in the use of intercepts.
Early on, FESS - or the Far Eastern Security Service -
broke Japanese codes, but the code-breakers were swamped.
They had only seven people monitoring Japanese traffic
for the whole of Asia, the Americas and the Pacific.
And there was no appetite in Whitehall
for taking a hard line against Japan.
They want to turn a blind eye.
They're worried about the consequences
for diplomatic relations with Japan.
And at this critical moment of British weakness, Japan struck.
In 1931, Japanese troops invaded Chinese Manchuria -
Japan's march to war had begun.
In response, the British began construction works here
to turn Singapore into the biggest and most fortified naval base in the world.
The cost was then an astonishing £50 million -
£2.5 billion today.
The dry dock alone was 28 miles square.
Enormous 15 and 16-inch guns
were built to repel any attack from the sea.
Just a year later, it was discovered that the Japanese
had secretly bought plans of the base
from a British serviceman called Roberts.
In 1936, MI5 stepped up their game in the East
and sent out a new station officer to Singapore.
He worked closely with Army intelligence on the ground.
British strategists assumed that any attack on Singapore
could come only from the sea.
But Army intelligence officer Joe Vinden had doubts.
He investigated the possibility of an attack by land
after an invasion of Malaya.
In the winter of 1937, Vinden sailed up the east coast.
'We landed on several beaches from a dinghy,
'and came close in shore all along the coast.
'The beaches presented no difficulty to any landing party.
'The defence scheme as laid down considered that any attack
'during the period of the Northeast monsoon
'from November to February was impossible due to rough seas.'
What Vinden saw convinced him
that an attack would come by land via Malaya.
'I learnt that during this period,
'several thousand Chinese landed on the east coast every year.'
Vinden even predicted the place the Japanese would come ashore-
Kota Bharu.
This would render Singapore's new fortifications redundant.
Vinden recommended the cancellation of additional guns
priced then at £15 million - that's £747 million today -
and that the money should be spent on new planes instead.
His advice was ignored and the new MI5 station officer retired.
Japanese spies were now everywhere, and not just Malaya.
Their tentacles stretched across the Pacific to the United States.
They even had agents in Pearl Harbour.
The base wasn't just crucial to the United States -
Churchill believed the American fleet
would deter any attack on Britain's colony of Singapore.
Yet incredibly, one of Japan's key agents at Pearl was now British.
He was the man who, back in the 1920s,
had taught Japan's pilots to fly from aircraft carriers
- Frederick Joseph Rutland.
Rutland had turned his technical expertise to espionage.
This is a fascinating document. MI5 are saying here,
"He used sea-going craft to investigate the harbour" -
this is in the United States -
"Taking moving pictures of any warships there.
"He is an expert 16mm movie cameraman."
Later, in a confession to intelligence officers,
Rutland would state...
'As to my duties, I was to report in peace time
'whether people were in favour of war,
'when war appeared to be imminent,
'whether the Americans were really going to war,
'the dispositions of the fleet.
'I fixed up a letter code -
'A was for aircraft, B was for battleships,
'C was for carriers, D for destroyers.'
Rutland's activities aroused suspicion
and the FBI were soon on his case. His every move was being followed
as they waited for the right moment to pounce.
In Britain, the naval pilot who'd already come close to prosecution
as a Japanese spy was now a distinguished public figure.
Sempill had commanded the highest pillar
in Britain's flying establishment -
president of the Royal Aeronautical Society.
In 1934, he inherited the family title as the 19th Lord Sempill
and took his seat in the House of Lords as a Conservative peer.
Society would regard him as someone with real integrity.
But Sempill has an ideological affinity
with militarist right-wing regimes.
In 1937,
Japan, now an ally of Nazi Germany, invaded China.
That year, Sempill welcomed a Japanese delegation
to Croydon airport.
Their aeroplane's name - Kamikaze -
was a chilling premonition of the shape of things to come.
'The airmen are officially welcomed by the Master of Sempill.'
British aviation is very proud indeed
of the splendid flight that has just been accomplished
by our two Japanese friends.
APPLAUSE
But there's evidence that Sempill also maintained
his secret links with the Japanese.
The records on Sempill from the 1930s
seem mysteriously to have disappeared.
But one surviving MI5 document from 1940 mentions that from 1931,
he was a paid consultant for Mitsubishi, which he knew
built aircraft for Japan's rapidly-expanding carrier force.
By then, she already had 130 planes
and three carriers.
The Japanese use a number of commercial fronts for espionage
so some of these major military industrial combines like Mitsubishi
are effectively conducting espionage for the Japanese government.
The same report also suggests
in addition to his Japanese sympathies,
another motivation for Sempill's actions.
He's somebody who seems to live beyond his means.
As far as we know from MI5 material,
he's running a hefty overdraft
and clearly, if the Japanese are willing to pay
substantial sums of money for access
and other governments are as well, it would be very tempting.
He was running a £13,000 overdraft.
That's nearly £750,000 by today's money.
Sempill wasn't just pro-Japanese.
Another line in the same report
mentions his membership of pro-Nazi organisation The Link.
He was also on the council of The Right Club,
whose objective was "to expose organised Jewry
"and clear the Conservative party of Jewish influence."
In September 1939, war in Europe broke out.
Winston Churchill returned to government
as First Lord of the Admiralty.
Astonishingly, Lord Sempill also joined the Admiralty.
Sempill gave a specific assurance
he would have no further discussions with his Japanese friends
on service matters.
Despite that, when the manager of Mitsubishi in London
was arrested for spying in August 1941,
at a time when relations with Japan were rapidly deteriorating,
Sempill intervened to secure his release.
MI5 noted...
Makehara was released after two days
and Sempill telegraphed, "Delighted results,
"proud to help, working hard cause."
The British government doesn't detain foreign nationals lightly
so these people are under suspicion of espionage
and Sempill is working to get them off.
At this precise moment, the two great leaders of the Western powers,
the British Prime Minister Winston Churchill,
and American President Roosevelt,
were meeting face to face for the first time.
Churchill was desperate to get Roosevelt
to join the war against Hitler.
Their discussions were held in total secrecy.
On board the Prince of Wales, with the Royal Marine Guard of Honour,
was Peter Dunstan.
All we knew, that there was a conference
between Churchill and Roosevelt
and that was in the officers' quarters in the rear of the ship
which was taboo to anybody
and so we didn't know what was going on.
All we knew, it was a conference between the two great men.
Later that month,
Churchill received news from British intelligence about the meeting
which filled him with horror.
This document is so sensitive,
it was classified for 60 years.
This is a detailed account of that meeting
sent from the Japanese Embassy in London
back to Tokyo.
We have this document
because the British codebreakers at Bletchley Park
intercepted and decoded this document
and shortly after the Japanese send this detailed account back to Tokyo,
it's on Churchill's desk.
This is not the sort of account that you could put together
through reading the coverage in the newspapers.
This is the inside story of the Placentia Bay meeting.
So essentially, what this points to
is that the Japanese have excellent sources in and around Churchill
and they have the inside track on that meeting with Roosevelt -
all the details about, for example,
the war against the Germans in the Atlantic.
And you can see Churchill's handwritten minute on this document,
"Pretty accurate stuff."
The fact that the Japanese knew all this about that meeting
means someone British was feeding them with the information.
How does that make you feel?
I'm absolutely shocked
to know that that...
Just, just cannot comprehend that that should have happened.
And how it happened or where it happened,
I just can't...
can't answer that question.
To this day, no-one knows who passed these secrets on
but the pool of candidates is very small.
We know who the Japanese informants are around this time
and perhaps the most important one,
certainly the most important one with access to Churchill,
is Lord Sempill.
There was worse to come.
A few days later, MI5 told Churchill
that the Japanese had information about his inner circle.
He demanded evidence.
A month later, after a surveillance operation,
it was presented to him with the names of two sources.
One was Sempill. The other had been with him in Japan.
This is a Prime Minister's personal minute.
It's from Churchill to Eden
and it's the 20th of September 1941.
"I regard the attached as most serious.
"At any moment, we may be at war with Japan,
"and here are all these Englishmen, many of them respectable,
"two of them I know personally,
"moving around, collecting information
"and sending it to the Japanese embassy.
"I cannot believe the Master of Sempill and Commander McGrath
"have any idea what their position would be
"on the morrow of a Japanese declaration of war.
"Immediate internment would be the least of their troubles."
"It is impossible for Lord Sempill
"to continue to be employed at the Admiralty."
Sempill was told he had to leave his job
but when Churchill heard the news,
he backtracked.
"First Lord,
"I had not contemplated Lord Sempill
"being required to resign his commission
"but only to be employed elsewhere than at the Admiralty.
"The matter should be treated as one of employment
"and not one of status."
You wonder if it's something to do with his aristocratic background.
The problem of course is to recall in this,
he's actually a member of the House of Lords
and he has friends, presumably, still within the Conservative party
who could create difficulties if he was interned.
What Churchill's realising is that
here is someone that MI5 has been watching since 1925
and Churchill's actually been giving this person classified information
and in some ways, it's bad for Sempill
but it also looks very bad for the British government.
Once again, Sempill had been let off the hook -
this time by Churchill himself.
On the 7th December 1941,
a Japanese fleet was sailing across the western Pacific Ocean.
Its air arm now surpassed both Britain and America's,
thanks largely to the Sempill mission
and his illegal supply of technical information afterwards,
exposed by MI5 intercepts.
Armed with this know-how,
the Japanese embarked on a secret naval operation
that would change the course of history.
Many of their planes were Mitsubishi Zeroes.
They could outperform any Allied aircraft.
The first Mitsubishi to land on a Japanese carrier
had been flown by a British pilot 17 years before.
The Japanese had perfected the technique
with the help of British air ace Frederick Joseph Rutland.
The use of torpedoes, which hung from their chasses,
had also been taught by the Sempill mission.
The commander of the fleet, Yamamoto Isoroku,
had become vice chief of the naval air base
which Sempill had overseen 19 years earlier.
Simultaneously, another fleet
sailed across the Gulf of Thailand towards Malaya.
Its objective -
to land a Japanese invasion force here at Kota Bharu,
just as intelligence officer Joe Vinden had predicted.
From pillboxes like this one,
British and Indian troops put up stiff resistance.
Churchill was confident that if they could just hold on,
reinforcements from Pearl Harbor would soon be on their way.
Two hours later,
Yamamoto Isoroku ensured that hope was extinguished.
In two waves, Japanese planes launched from carriers
attacked the fleet at Pearl Harbor.
Small aircraft with large bombs,
the secret technology which first prompted MI5's phone tap of Sempill,
destroyed the American fleet.
Yamamoto's right-hand man in planning the attack
was Takijiro Onishi. He'd been personally trained by Sempill.
With the US fleet at Pearl Harbor wiped out,
the only British ships available in the Far East
sailed from Singapore to intercept the Japanese.
Led by the finest battleship in the Royal Navy, the Prince of Wales,
on which Churchill and Roosevelt had met just three months earlier,
they were the only hope of stopping the invasion fleet
but had no air cover.
They were spotted by Takijiro Onishi's navy air fleet.
Now the British would learn just how well Sempill had trained Onishi,
who planned the attack.
83 aircraft dived with heavy bombs and torpedoes.
Underneath was Peter Dunstan.
One of the first torpedoes hit the Prince of Wales
on the port forward propeller shaft.
It ripped a great big hole in the Prince of Wales
and she dropped down to the stern
with the amount of flooding water that came in.
After the Japanese had stopped bombing us...
..and she was going down,
we were told to abandon ship.
The Prince of Wales and HMS Repulse were sunk
with a loss of nearly 900 lives.
The same day,
Sempill was caught making calls to the Japanese Embassy,
a full three days after hostilities had begun.
Who the hell are you?
Astonishingly, he made more calls on the 13th of December.
- We've been listening to your calls. - I don't give a damn who you are.
When his office was searched, he was found to have Admiralty files
he was supposed to have surrendered three weeks earlier.
Despite all of this,
Sempill was never prosecuted.
On the 15th of February 1942,
Singapore fell.
100,000 troops were taken prisoner.
The majority were shipped to Japanese concentration camps,
where a quarter died in horrific conditions.
In a secret session of the House of Commons, MPs demanded an enquiry
to explain how this tragedy could have happened.
It was blocked by Churchill himself.
If it had gone ahead, it might have revealed
that for nearly 20 years before the surrender,
British officers had provided the military secrets and know-how,
first legally, and then covertly,
that enabled both the raid on Pearl Harbor
and the capture of Singapore.
Rutland was deported to Britain, where he was interned for two years.
He comes out towards the end of the war,
destitute. He eventually ends up killing himself
by putting his head in an oven in a bedsit in London.
Sempill is given a choice when Churchill discovers his activities.
He can either resign his naval commission
or else he's given the choice
of taking a position up in Northern Scotland.
Rutland isn't part of the British elite and Sempill is.
Lord Sempill died in 1965.
He went to his grave treasuring a very special possession -
the Order of the Rising Sun,
given to him for what the Japanese Prime Minister called
"the splendid results, almost epoch-making,
"that have been brought about in the Imperial Japanese Navy."
In the wake of the sacrifice at Pearl Harbor
and the fall of Singapore,
these words took on an added resonance.
Japan had wounded a superpower
and crippled an empire.
Worse still, it was done with the help of people
the Japanese were supposed to be fighting against.
For Britain, the price was enormous.
She would never be the dominant power in Asia again.
Subtitles by Red Bee Media Ltd