Podcast

# On the Record: MI5: Official Secrets

In celebration of our new exhibition featuring secret files and spy gadgets,
this episode of On the Record delves into the real world of espionage – one
perhaps more intriguing than fiction.

Published 17 April 2025 by [Mark
Dunton](https://www.nationalarchives.gov.uk/people/mark-dunton/), [Chloe
Lee](https://www.nationalarchives.gov.uk/people/chloe-lee/) and Gill Bennett

![Grainy photograph of two men standing at a bus stop. The men face away from each other. The photo seems to have been taken covertly.](https://www.nationalarchives.gov.uk/media/images/KV2-61_Tate_left_an_xxVLE5p.941d5183.fill-1800x720.format-jpeg.jpegquality-60.bgcolor-fff.jpg) 

About this image 

Agent Tate and Lt Commander Mitinori Yosii at bus stop, 1941. Catalogue
reference: KV 2/61.

Spy fiction has captivated our imagination for decades, but the truth behind
Britain’s security service is even more fascinating than the high-stakes capers
of the movies. At The National Archives, we hold the real files—declassified
documents that reveal the actual operations, successes, and sometimes failures
of MI5 since its creation in 1909.

Our guests include Gill Bennett, a historian specialising in secret intelligence
and former Chief Historian at the Foreign Office, and Mark Dunton, Principal
Records Specialist at The National Archives.

## Listen to the episode

Listen

### MI5: Official Secrets

 

Your browser doesn't support HTML5 audio. [Download the audio
file](https://www.nationalarchives.gov.uk/media/media/OTR_-_MI5_-_March_2025_-_v4.mp3).

Audio transcript for "MI5: Official Secrets"

Chloe Lee: James Bond, George Smiley, mysterious gadgets and coded messages. Spy
fiction has captivated our imagination for decades, but the truth behind
Britain's security service is even more fascinating than these high-stakes
capers.

Here at The National Archives, we hold the real files, declassified documents
that reveal the actual operations successes and sometimes failures of MI5 since
its creation in 1909 in fact, we're about to showcase many of these files, plus
spy gadgets and other objects in a new exhibition that opens at our site in
queue on April 5th.

I'm Chloe Lee, a record specialist at The National Archives. I also host our
podcast On The Record at The National Archives, uncovering the past through
stories of everyday people.

In this episode, as we announce the new exhibition, I want to explore the
remarkable history of MI5 through true stories that go beyond anything dreamed
up by Ian Fleming or John le Carré. A female agent who infiltrated communist
circles in the 1930s and a Danish double agent whose deception during the Second
World War saved countless allied lives.

To guide me through these now declassified files, I've invited two guests who
have unravelled the real-life mysteries within our collections.

In this episode, we've got contributions from Gill Bennett, a historian who
specialises in secret intelligence and former Chief Historian at the Foreign
Office. Gill will be setting the context.

And in the studio, I'll be speaking to Mark Dunton, Principal Records Specialist
at The National Archives. Welcome to the studio, Mark.

Mark Dunton: Thank you. Chloe, it's great to be here.

Chloe: I'm really excited about our conversation today.

Mark: Yes, indeed.

Chloe: So I need to know exactly what MI5 is and how it came into being. So
let's first hear from Gill explaining that context.

Gill Bennett: MI5 grew out of the creation of the Secret Service Bureau in 1909
and that was a body set up by a committee of imperial defence in expectation
there might be a war with Germany. So the body was set up to look at espionage
against the United Kingdom. It started off doing foreign and domestic espionage,
but within a year, in 1910 it split into two. MI5, the Domestic Intelligence
Bureau, and what was then called MI1c, and later became the Secret Intelligence
Service, the overseas intelligence agency. I should point out that MI stands
merely for ‘military intelligence’. And of course, the domestic side of it is
worried about, for example, trying to find where there are German spies in this
country. When war does break out, that is one of the principal focuses of MI5
work, and they were extremely successful in detecting German spies.

But the important contextual point is that the First World War itself was a
tremendous technological catalyst for developments in both domestic and foreign
intelligence, and indeed (we haven't got to that yet) with signals intelligence.
So lots of the early cases by MI5 were very formative for what happened later,
they learned a lot. They developed new techniques about listening, intersecting
mail, censorship, detecting spies, about all kinds of things which were going to
be, actually, the foundation of their work for many years to come.

So by the end of the First World War, MI5, like all the intelligence bodies had
grown hugely. Started off very small and ended up really quite large, and it had
a very successful war.

Chloe: It's such a fascinating context. Now, Mark, is there a case from our
records that demonstrates MI5 growing capabilities in the First World War?

Mark: Well, yes indeed, there's the Carl Muller case. Now, Carl Muller, he came
over to England in 1915 with a group of refugees. He claimed to be Russian, but
he was in fact German, and he claimed to be a shipping broker, but in fact, he
was moving around the country and reporting on information such as troop
movements.

Chloe: I see, I see.

Mark: Yes, he was sending letters to German intelligence in Rotterdam. These
letters seem to be innocuous, but he was actually using invisible writing, using
lemon juice between the lines, and giving them various info about as I say,
items like troop movements, resources, that sort of thing.

The letters were intercepted by the postal censorship department, which was
working with MI5. And what they did, was they passed a warm iron over the letter
because they were suspicious about it. The warm iron then the secret writing in
lemon juice emerged, yes, indeed. And so the authorities started looking for
Muller. He did have an accomplice. He was a bit of a stooge in all this, a guy
called John Hahn, who was a disgruntled German baker based in Deptford. The
trail originally led there, but then, they found Carl Muller in his lodgings, I
think, in Bloomsbury, and when he was arrested, they found a lemon in his
dressing table drawer. And they said, why have you got that lemon? And he just
pointed to his teeth and said, you know, sort of saying my teeth, as if he was
using it to clean his teeth. And rather unsurprisingly, they didn't actually
believe him.

Chloe: So whilst they uncovered the invisible ink, they didn't necessarily know
how he was making the invisible ink. That wasn't until they discovered this
lemon.

Mark: Yeah. I mean, the lemon was kind of, in a way, real proof of guilt,
really, yes, because they already knew that lemon juice was being used, and in a
way, it's one of the things that helped to convict him. So he was tried, found
guilty of espionage and actually executed by firing squad at the Tower of
London.

Chloe: So this is a real example of early forensics. Can we say that?

Mark: This case shows how amazingly effective the postal censorship department
was. It shows the increasing use of forensics at this time. Because they even,
have a specialist who even analyses the cellular matter on the pen nib, you
know, and analyses it and says, this is lemon juice. You know, it's all very
precisely done. And the other thing is, is the deception angle, because MI5
pretended that Muller was still alive after his execution, still sending
messages to his German masters. And this was a forerunner of the double cross
operation in the Second World War. And the other thing I must just tell you is
that they pretended to be Muller. They were asking for more funds. Germany send
more funds to us. Germany did send more funds, which MI5 used to buy a car,
which they then christened The Muller, although apparently, the Treasury
reprimanded them for unorthodox use of expenditure.

Chloe: And so we've got the lemon in the exhibition?

Mark Dunton: We have we've got the very lemon that was found in his dressing
table drawer in the exhibition. It's black and shrivelled and compressed, but it
is the lemon, and it forms part of the archive.

Chloe: Let's move on to the interwar period. We can hear from Gill on MI5’s
focus during that time.

Gill: The focus of MI5 during the interwar years, between 1918 and 1939 was like
all of British intelligence against the Soviet Union following the Bolshevik
Revolution of 1917 that had brought a Bolshevik government into power in Russia.
The perception of the Soviet Union as a hostile threat and employing espionage
and sabotage against Britain, it was not a red under-the-bed scare. They really
were doing that. And although during the 1930s MI5 and all the agencies would
gradually move their focus as the Nazi threat grew in most of these years, the
enemy is the Soviet Union and its extensive espionage threat.

However, after the First World War, MI5, like all the rest of British
intelligence, was starved of money. It was cut down. The country was in a very
bad way economically. The agency was cut back. Lots of people who had worked for
it went back to their normal jobs after the war, and so you were operating, at
least initially, with very small resources to try and do a very big job.

Chloe: It's also important to know whether the threat from Communism was the
only concern during this time.

Gill: During the 1930s Britain is actually facing a number of threats all at the
same time. So obviously there's the Soviet threat, but there's also the rising
threat of rearming Nazi Germany, which after 1936 was also working with Italy
and with Japan. So there are threats on all sides, all of which pose a threat to
domestic espionage for MI5, as well as for the other agencies. The threat does
shift, very largely towards Germany during the 1930s and MI5 had to really shift
its focus while still being underfunded and understaffed and under-resourced. So
it was definitely a challenge to meet the threats. Of course, they were worried
about, still, worried about the threat of German spies in Britain. They were not
as worried as they should have been. But of course, they didn't know this at the
time that, of course, we now know, during the 1930s a number of important Soviet
spies were recruited in the UK, including the ones we think of as The Cambridge
Five. So it'll be Burgess, Maclean Cairncross, Blunt and Philby.

Chloe: Now we have that background Mark, let's get into the fascinating stories
of Maxwell Knight and Olga Gray. Can you tell me about them?

Mark: Yes, yes, indeed. So you have Charles Maxwell Knight. Now, I think he was
rather an eccentric character, but he was a legendary spymaster, particularly
busy in the 1930s and he liked to use agents to infiltrate what was seen as
subversive political organisations. It was a sort of softly, softly approach.
They would be the ears and eyes looking out for vital information. He was
certainly keen on building relationships with his agents rather than just giving
orders. Now, the thing about Knight was, that he was particularly keen on the
use of female agents because he thought that women had a sort of natural guile,
and some of the language that he used to talk about this would really jar with
our modern sensibilities. But in some ways you could, you could say he was quite
progressive. Most people at this time would take the view, perhaps that a
woman's place is in the home kind of thing.

Chloe: So maybe he saw women as particularly sharp tools when it came to
building relationships with their targets, right?

Mark: Yes I think he did. And you know, so I think in some ways, he thought
women had an advantage over men in this respect, as agents.

Chloe: And so is Olga Gray an example of that?

Mark: Yes, very much so. So Olga Gray, was in the early 1930s she was about 25
she was a trained commercial secretary, and she sort of, she did this sort of
slow infiltration into communist organisations, including the Communist Party of
Great Britain, and eventually, she became the leader Harry Politt’s Secretary.

Chloe: Wow. So really at the ear of leaders.

Mark: That’s right. So she was there, you know, listening, reporting back. I
mean, there was a very strong fear of communism in this period. And MI5 was
concerned for a long time about the Communist Party of Great Britain, perhaps
rather too much. When MI5 looks back on this history over the whole period, they
think maybe there was a bit too much concentration on this organisation. You
know, for her, the files, I think, indicate that at times, all of this was quite
a strain, and took its toll on her personally.

Chloe: You're holding two different identities at once, aren't you?

Mark: You are, that's right. And they sent her on a mission to India, for
example. I think there were times when she felt like giving up. But the thing
about Olga Gray is that she helped to break up a major spy ring, which shows the
Soviet threat. This was the Woolwich Arsenal spy ring. There was a character
that she was introduced to by Harry Pollitt, I think, called Percy Glading. And
he was, he was very much trying to get defence secrets out of Woolwich Arsenal
(where he used to work) and passing them to the Soviet Union. And Olga Gray
foiled, it's largely down to her actually, that this was foiled.

Chloe: And that’s all because she was a trusted person, right?

Mark: Exactly, they did trust her. Percy Glading trusted her, and she gave
evidence under a code name, Miss X. So she appeared in court using this code
name. The press at the time loved it, because, of course, this was something
new. This was something very exciting. You know an attractive woman who was a
spy for us if you like…

Chloe: So Olga was monitoring these communist activities. She was feeding back.
but we also heard from Gill about this growing threat from Hitler's Germany and
a homegrown British fascism. Can you tell us a bit more about that Mark?

Mark: Yes, certainly. So I think MI5 when they look back on this history, admit
that they were rather slow to appreciate the dangers posed by the rise of
fascism, fascist groups at home. And I'm thinking particularly of Oswald Mosley
and the British Union of Fascists. But when MI5 discovered that they were
receiving foreign funding from Mussolini's Italy, they became more alarmed. And
in the records, you see Vernon Kell (he was the first director general of MI5),
you can see his reports about the British Union of Fascists, and he makes some
very prescient comments about how they're copying Nazi methods very closely.

MI5 applied more than once for a Home Office warrant on Mosley. This meant that
his correspondence would be intercepted, perhaps his phone calls tapped, but
successive home secretaries blocked this. They seemed to regard Mosley as
fundamentally patriotic, although in the end, Mosley was interned in 1940.

MI5 also tried to warn the government around the late 1930s about the real
danger posed by Hitler's Germany and his expansionist aims, but the government
were not prepared to listen to MI5 at this time.

Chloe: So let's move on to the Second World War, which seems to have been a
pivotal period for MI5. Gill can explain how MI5 innovated during this time.

Gill: As with the First World War, the Second World War was a tremendous
technological boost for MI5 and for all the intelligence agencies. In fact,
their work became very important to each other, not just MI5 and what is now
called MI6, and also of course, what was then called the Government Code and
Cipher School, the signals intelligence agency, now GCHQ. Deception for all the
agencies, and particularly MI5, is a major focus of the effort, and they all
work together on this. And of course, MI5’s big achievement, which still remains
absolutely astounding when you hear about it is the Double-Cross System. Which
is basically turning German spies and getting them to work for Britain instead.

The other agencies played a part in that, It's important to remember. What
Bletchley Park could provide, for example, from intercepts, which would let them
know what the Germans did not know. For example, you might want to give your
bogus agents what we call chicken feed, which means feeding them some
information which the Germans would be interested in, and which indeed is of
interest and might even be true, but is not giving away anything that you don't
want to give away. But it is enough to entice them so that they believe what
you're telling them.

To decide what could safely be revealed and what could mislead is very
difficult. Important contributions were also made from the intelligence effort
of countries that had been overrun, like Poland, who brought their intelligence
services to London, as did some of the French. So they're all working together,
but MI5 has an extremely good Second World War, and the double cross system is
the pinnacle of its effort.

Chloe: Mark, who's an example of a double agent that folks might not have heard
of before?

Mark: Well, there's Agent Tate. Now he was Danish born, and his real name was
Wulf Schmidt, he landed by parachute on a spy mission for Germany in September
1940. He was quickly arrested and interrogated, and he was interrogated at Camp
020 on Ham Common, where suspected spies were interrogated. We have the actual
transcripts of his interrogation, featuring in the exhibition Wulf Schmidt
(Tate) becomes a double agent and the longest serving agent, wireless agent, in
the Double-Cross System.

Chloe: So he begins to work for the British?

Mark: He does that's right, sending misleading information to the Germans and
pretending that all is okay with his mission in Britain. The Germans trusted him
completely, and he was awarded the Iron Cross, I think, in 1941.

Chloe: So utterly convincing?

Mark: Yes, indeed, you know, they really did. I think there was a quote from a
senior German military officer who described him as ‘a pearl’, you know, ‘in our
network’. This false information that Tate was sending the Germans made them, it
made them make some significant mistakes in terms of military strategy. An
example of this is that thanks to reports sent by Tate, German U-boat commanders
were told you must stay clear of an area south of Ireland because there's a big
minefield there that our agent has warned us about. And this had the effect of
saving a really important convoy route into England. It probably saved countless
lives. Another example is that he gave them false information about where the V1
and V2 weapons - where those flying bombs were landing in London. This forced
them to change their trajectory so that they didn't fall so much in urban areas.
Again, you know, I'm sure many, many lives were saved. So he did some heroic
work for this country in the Second World War.

Chloe: And as part of the exhibition, we've produced some restaged audio of this
interrogation. Tate's interrogation is based on the official documents that
you've just referenced. Let's listen to a portion of that now:

Schmidt

I beg you to let me talk with the Danish Consul

, if possible.

Interrogator

No, no, you are a spy. What I want is the truth?

Schmidt

Yes, I will tell the truth or what I know. How can I do so? I mean, I came here,
I fight in Denmark with a German. How can I how can you tell me?

Interrogator

How did you come here?

Schmidt

With a boat from Esbjerg

Interrogator

No, you didn't.

Schmidt

Yes.

Interrogator

No, you didn't. When did you come here?

Schmidt

On the 10th, on the night of the 10th and 11th of July.

Interrogator

That is a lie. I know that is a lie. Don't come here and tell me lies. You might
just as well tell me the truth. We know a great deal about you. The sooner you
make up your mind to tell me the truth, the better.

Chloe: So we know that Schmidt didn't eventually get turned into a spy for
Britain. But Mark, what do these interrogation records reveal about MI5’s
methods?

Mark: One of the officers who interrogated Tate was Captain Robin ‘Tin Eye’
Stephens, who had an ever-present monocle and a very fierce appearance. And he
very much used methods of psychological pressure on these suspected spies. For
example, the suspected spy would be made to stand. He would bark things at them,
they would perhaps be deprived of sleep. But he forbade the use of physical
violence because he believed it was counterproductive. But you can see a
relentless determination, if you like, to crack the suspected spy and then see
if perhaps they can be used against Germany. Turned into a double cross agent
working for Britain against Germany. Not all of them were suitable for that
purpose, and some were executed.

Choe: Moving into the Cold War period, Gill knows a lot about the main
challenges facing MI5 in these years.

Gill: MI5, like the other agencies, suffered some of the same problems as they
had after the First World War, and indeed, after the Cold War, the same because
they're cut back. People always think, well, we don't need spies anymore, so
they're short of resources. At the same time after the Second World War, what we
now call the Cold War, really gets going, a split between East and West. You get
more and more espionage and sabotage carried out by the Soviet Union and indeed
by other countries within the Soviet influence. So it was a very busy time.
You've also got a question of atomic espionage, several prominent atomic spies,
such as Fuchs for example, and we now know, of course, that there were a number
of spies, some of the Cambridge Five in the early 50s. Burgess and Maclean go to
Moscow. It begins to become apparent that there have actually been significant
Soviet agents operating within the British system. This obviously gives MI5 a
big problem.

By the early 60s, there was a complete rush of what you might call ‘spy cases’,
the Portland Spy Case, the George Blake case, a very important one in 1961, and
then he escaped from prison. And of course, Philby, who had been suspected in
the 50s and discharged from SIS but not prosecuted, does, in fact, finally
defect and go to Moscow in 1963. The final defection of Philby is a really big
blow to the British intelligence community as a whole. Now MI5, all of them, and
MI5 and MI6 form together a joint committee to examine past operations. It's
called the Fluency Committee, to try and see if they might have missed any
spies.

Now, during the 60s, meanwhile, the Soviets are throwing a huge amount of effort
into espionage at the Western world, the sort of thing that's been documented in
the Mitrokhin Archives. And during the 60s, MI5 really can't cope. They cannot
follow all the people in the UK that they think are Soviet spies. And that is
what produces in 1971, what is still the single largest expulsion of
intelligence officers, when the UK Government expelled 105 Russian intelligence
officers, under Operation Foot.

Chloe: Those are some fascinating cases. Mark, do we have records about any of
them?

Mark: Yes, we certainly do. In fact, there's a huge amount of documentation
here, and the files are so rich, you know, they've got surveillance reports and
transcripts of bugged telephone calls and transcripts from other listening
devices. So the files are just amazing. Just in January this year, we had a
major release of MI5 records, many of which concerned notorious Cambridge spies
such as Kim Philby, Anthony Blunt and John Cairncross.

For example, we now have the confession statement from Kim Philby handed to an
MI6 officer in Beirut when Philby was confronted about being a spy for the
Soviet Union. Now it's very much a partial confession. Also in the files, we
have a dialogue between Philby and the MI6 officer who's been sent out to Beirut
to confront him, and Philby admits passing information to the Russians about the
would-be Soviet defector Volkov.

Now Volkov, Constantine Volkov was an NKVD officer, and Russian intelligence
officer, and back in 1945, he approached the British. This was in Istanbul
Turkey, and he offered to defect. In fact, he said, If you can give me political
asylum and some money, I can give you a lot of secrets about Soviet
intelligence, and also, by the way, you have some spies operating at home. Some
people in key positions at home are acting as agents for the Soviet Union.
Philby got wind of this and tipped off the Russians. The Russians moved quickly.
They kidnapped Volkov and his wife drugged them, took them to Moscow, brutally
interrogated them, and then executed them. That was down to Philby. So Philby is
admitting his culpability in this terrible business.

Chloe: So Philby was part of the Cambridge Five recruited by Russia in the
1930s. How damaging was the Cambridge Five operation to British security?

Mark: Very damaging I would say Chloe. Because you know that really, between
them, they penetrated all the major institutions of British state security, and
they were operating, you know, in the 30s, 40s, 50s, you know, so many secrets
were passed to the Soviet Union, including nuclear sort of information, and many
operations were compromised.

So, you know, there were scores of deaths as a result of some of the information
passed to the Soviet Union, particularly by Philby. The other thing is that it
was a huge resource drain on MI5 because, you know, for such a long time they
were trying to find out, well, who are all the individuals in this Cambridge
Five network.

Chloe: I guess they might not have necessarily known there were five, right?
There must have been paranoia over other possible spies working inside
intelligence services and the wider government.

Mark: That’s right. It led to a huge sort of distrust, and they realised we must
have more exacting vetting procedures in future. There needs to be more careful
checks carried out on people who are working in these high positions, so they
did learn from it, but there was a terrible price that was paid for all their
activities.

Chloe: This conversation for me Mark, it's really revealed that whilst there is
this very glamorous kind of narrative about spies and spymasters, there's some
real impact that really tears people's lives apart when it comes to this kind of
history. I can imagine, there are lots of challenges, researching and writing
about an organisation that, by its very nature, operates in secrecy. Mark, what
would you say is the one big challenge that historians face when studying MI5?

Mark: Yes, well, I think the challenge really is that these cases of espionage
are very complex and of course, the devil is in the detail. And so, you know,
I'll give you an example. On the day after war broke out in August 1914 the Home
Secretary, Reginald McKenna, announced in the House of Commons, that 21 spies
and suspected spies had been arrested within the previous 24 hours.

But when you go and look into the files and what the files show, historians have
found that actually there are some discrepancies, and they're quite significant.
There are several different lists of these spies. There are real doubts that
they were all arrested at the same time. And there are variations with the
names. As a historian, you have to be forensic in looking at the records, you
have to sift through the evidence and come to a judgment about things. But you
know, these records from MI5 are so rich, and I love the spirit of openness in
which MI5 have transferred these records to us and made them available for
everyone to see.

Chloe: Finally, on April 5, The National Archives opens a new temporary
exhibition about MI5. Mark, what makes this exhibition particularly significant?

Mark: Well, I think the exhibition is certainly groundbreaking because this is
the first time that MI5 has collaborated with a public institution in telling
its history. So again, I think there's a great spirit of openness there. The
exhibition tells the human stories behind intelligence work, and I think, you
know, there's a lot of food for thought, actually, from this exhibition, you've
got real people making difficult choices, sometimes at great personal risk, such
as Olga Gray, for example. And I think there's one or two other things I think,
you know, MI5 is often mythologised in popular culture.

You know, often, if you just say ‘MI5’, it has a certain allure. And people
might start thinking about James Bond, you know, that kind of fantasy world. But
the exhibition, I think, is much more grounded in reality, and it's showing - so
it's showing the reality of things, the historical fact, rather than the spy
fiction. Although, of course, it's true. You know stories of espionage and the
gadgets and equipment used by spies. This is fascinating stuff. It is
intriguing, but we see the evolution of intelligence work over time as well. So
really, I think people will find this very rewarding to see this exhibition.

Chloe: That's great. And can you share maybe three highlights that visitors can
look forward to seeing at the exhibition?

Mark: Yes, well, it's always a difficult choice just picking three, but I think
I can do this. So I would say seeing the actual lemon that was found in Carl
Muller’s lodgings that helped to convict him of espionage, I think, you know,
that's one fascinating item. Also we have actors who are reading a transcript of
a bugged conversation in the Portland Spy Case, which has some almost
unintentionally comic aspects about it. It's fascinating. And then also, there's
a transcript which is derived from a listening device in the home of Klaus
Fuchs, the atomic spy. And they can hear so much detail that they even talk
about him stoking the fire in the grate you know, that's how closely they're
monitoring him back in about 1950 - so those are three examples, which I hope
will whet your appetite.

Chloe: Thank you, Mark, and thank you Gill. [The exhibition, MI5: Official
Secrets, runs from April 5th to September 28th 2025 at The National Archives in
Kew](https://www.nationalarchives.gov.uk/mi5-official-secrets/).

Thanks for listening to On The Record from The National Archives. To find out
more about The National Archives, follow the link from the episode description
in your podcast listening app. Visit nationalarchives.gov.uk to subscribe to On
the Record at The National Archives so you don't miss new episodes, which are
released throughout the year.

Listeners, we need your help to make this podcast better! We need to know a bit
more about you and what themes you're interested in. You can share this
information with us by visiting [smartsurvey.co.uk/ontherecord, that's
smartsurvey.co.uk/ontherecord](https://www.smartsurvey.co.uk/s/ontherecord/).

We'll include that link in the episode description and on our website. You can
also share your feedback or suggestions for future series by emailing us at
[OnTheRecord@nationalarchives.gov.uk](mailto:OnTheRecord@nationalarchives.gov.uk).

Finally, thank you to all our experts who contributed to this episode. This
episode was written, edited, and produced by Tash Walker and Adam Zmith of Aunt
Nell, for The National Archives. The audio of Agent Tate’s interrogation was
produced by Chocolate Films Video Production.

This podcast from The National Archives is Crown copyright. It is available for
reuse under the terms of the [Open Government
Licence](https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/).

You'll hear from us soon!

## Records featured in this episode

* From our collection
  :   WO 106/6292

  Title
  :   [War Office records on the formation of a secret service bureu](https://discovery.nationalarchives.gov.uk/details/r/C6074475)

  Date
  :   1908-1915
* From our collection
  :   WO 141/2/2

  Title
  :   [Espionage charges against Karl Muller](https://discovery.nationalarchives.gov.uk/details/r/C160067)

  Date
  :   1915
* From our collection
  :   KV 2/62

  Title
  :   [Security Service records on Agent Tate](https://discovery.nationalarchives.gov.uk/details/r/C6091970)

  Date
  :   1940-1943

## Further information

Past exhibition

### [MI5: Official Secrets](https://www.nationalarchives.gov.uk/whats-on/exhibitions/mi5-official-secrets/)

![](https://www.nationalarchives.gov.uk/media/images/OfficialSecretsWebsi_dZbqhLt.2e16d0ba.fill-600x400.format-jpeg.jpegquality-60.bgcolor-fff.jpg)

Find out more information about our new exhibition, including how to visit.

The story of

### [Karl Muller and the fatal lemon](https://www.nationalarchives.gov.uk/explore-the-collection/stories/karl-muller-and-the-fatal-lemon/)

![](https://www.nationalarchives.gov.uk/media/images/muller-lemons-t_5FMipk9.4106a48c.fill-600x400.format-jpeg.jpegquality-60.bgcolor-fff.jpg)

When can a lemon have fatal consequences? If it proves you are, in fact, a
wartime spy…

### [Research guide: Intelligence and security services](https://www.nationalarchives.gov.uk/help-with-your-research/research-guides/intelligence-and-security-services/)

This guide will help you to find records held at The National Archives of, and
relating to, the British intelligence and security services.

## Subscribe to On the Record

pod.link

### [Find the podcast on your preferred service](https://pod.link/1460242815)

On the Record is available wherever you get your podcasts.

## Tell us what you think

smartsurvey.co.uk

### [Fill in our survey](https://www.smartsurvey.co.uk/s/ontherecord/)

Listeners, we need your help to make this podcast better! We need to know a bit
more about you and what themes you’re interested in.

## Copyright

If you wish to re-use any part of a podcast, please note that copyright in the
podcasts and transcripts in some cases belongs to the speakers, not to the
Crown.

### Contact our Copyright Officer with queries

Email
:   [copyright@nationalarchives.gov.uk](mailto:copyright@nationalarchives.gov.uk)  Copy email address

## Authors

* ![Profile photo for Mark Dunton.](https://www.nationalarchives.gov.uk/media/images/mark-d.2e16d0ba.fill-128x128.format-jpeg.jpegquality-60.bgcolor-fff.jpg)

  **[Mark Dunton](https://www.nationalarchives.gov.uk/people/mark-dunton/)**

  Roles
  :   Author
  :   Researcher

  Principal Records Specialist (Contemporary records)
* ![Profile photo for Chloe Lee.](https://www.nationalarchives.gov.uk/media/images/Chlo_UfHe7DT.2e16d0ba.fill-128x128.format-jpeg.jpegquality-60.bgcolor-fff.jpg)

  **[Chloe Lee](https://www.nationalarchives.gov.uk/people/chloe-lee/)**

  Roles
  :   Author

  Records Specialist (Empire and Commonwealth)
* ![](/static/images/blank-profile.svg)

  **Gill Bennett**

  Former Chief Historian at the Foreign Office

## Help us improve this website

[Complete our short survey (opens in new tab)](https://www.smartsurvey.co.uk/s/DN07V0/?area=footer&source=http%3A%2F%2Fwww.nationalarchives.gov.uk%2Fmd%2Fexplore-the-collection%2Fon-the-record-podcast%2Fmi5-official-secrets%2F)

---

[Back to top](#top)