The Defector: The Untold Story of the KGB Agent Who Saved MI5 and Changed the Cold War

by Richard Kerbaj

The untold account of how, in 1971, the defection of a KGB saboteur in London led to the rescue of MI5 after a series of disastrous intelligence failures.

Drawing on newly declassified intelligence documents and dozens of interviews with spymasters, The Defector tells a startling story of a Soviet mission to plant fake Kremlin agents within British and American intelligence services, the paranoia that ensued, and how the actions of a genuine turncoat, the former KGB officer Oleg Lyalin, and the secrets he revealed resulted in one of the most dramatic and pivotal moments in the Cold War.

Lyalin led MI5 to rethink its relationship with the CIA. And his defection discredited a previous KGB defector, Anatoly Golitsyn, the darling of the CIA, and ultimately destroyed the reputation of the US agency's head of counterintelligence, James Jesus Angleton.

At the heart of Lyalin's story is a narrative entwined with lies, disinformation, Kremlin deception campaigns, intelligence failures by the CIA and MI5, and a tangled love life. Told in full here, for the first time, by one of this country's leading commentators on national security, it reveals how during the darkest moments of the Cold War one of the West's greatest achievements transpired as a result of MI5's break with the CIA.

The disclosure of the inside story of this historic event also comes at a time when there is a renewed interest in the relationship between transatlantic spy services—from the intelligence they share or hold back to the way they respond to their political masters and stand up to threats from Russia.

Genres: History, Nonfiction, Espionage, Audiobook, Politics

352 pages, Kindle Edition

First published September 4, 2025

Reviews

[Brendan (History Nerds United) · Rating 4 out of 5]

I think there are times where we glorify defectors too much. Often we get to see the person who realizes they are on the wrong side of history (or a certain Iron Curtain). But what if their reasons are less ideological? In fact...what if they just suck as people both before and after defection?

Say hello to Oleg Lyalin! Sure, Oleg made the "right" choice to run into the arms of the free world. Never mind it happened because he was actually just trying to get a better job back in Russia, that he was a philandering drunk, and was utterly obnoxious as an asset for the West.

He is the title character of The Defector by Richard Kerbaj. Well, sort of. There are so many defectors in this book that it's hard to pick just one! In fact, it's part of the problem for the CIA and MI5. Are all of these defectors the real deal or a ploy by the KGB to keep focus in the wrong places? I don't like revealing too much in spy books so we can leave it there.

Kerbaj does a pretty good job of telling this story with a lot of moving parts. I did feel like he interrupted the flow a bit too much with side stories. He never goes off on tangents that don't have any bearing on the story. But it did feel like a more focused story would have resulted in a better narrative drive without any slowdowns. It's not fatal to the narrative, and this is still a must-read for anyone looking for a Cold War spy fix.

(This book was provided as a review copy by Pegasus Books.)

[Gary · Rating 3 out of 5]

This is clearly a major work of research and interesting, however enjoyment of it is hampered by poor structure and avoidable typos. It’s major structural fault is that it’s disorganized, hopping backwards and forwards in history and taking far too long to properly engage with its subject.

[Jarred Manson · Rating 3 out of 5]

That was a tough read. The writing style was hard to follow and it seemed to focus on the small details rather than the overall idea of the book. Ironically, the epilogue was the best part....

[Ed · Rating 3.5 out of 5]

This is an interesting book about the Cold War spy games played between the Soviet Union, Britain, and the United States. It concentrates on defectors and the ways they changed how spying was done. Photos of the spies are also included.

[Christopher Vowles · Rating 3 out of 5]

Meandering account of spy wars.

[Lydia · Rating 4 out of 5]

This was an excellent book on the intelligence mishaps and wins that irrevocably shaped the Cold War. Very readable for non-fiction and clearly well researched, with access to the intelligence community and people who knew Lyalin.

It made me laugh out loud and gasp at different points?? Would recommend even to those who don’t enjoy non-fiction as a general rule!

[Andrew Macfarlane · Rating 3 out of 5]

this is an interesting time much of time. better in the last hundred pages initially I got the feeling that this was going to be more like a long newspaper article like the features in weekend American newspapers. There was a lot of irrelevant padding about the grandfather's and fathers of some of the future protagonists that in the added no great inspired context or helped the story in any way whatsoever. like with books about recent German history. even if they are about the 1980s several chapters are wasted giving a potted history of Germany since the 18th century. So here, the wartime exploits, the Tsarist actions of fathers and grandfathers gave no insight, no context and we're totally different to the actions of the majority characters themselves. they only served to pad out the book.

[Peter Jerram · Rating 5 out of 5]

This books brings perspective and clarity to a fascinating subject. A major addition to Cold War literature and exposes the destructive paranoia of JJ Angleton whose obsession with mythical traitors for 20 years hamstrung the battle between the democracies and the KGB. Terrific.

[Pirate · Rating 5 out of 5]

Engrossing read, giving a fascinating insight into the Russian secret services (NKVD/KGB/FSB) and how they operate both internally and externally. Oleg Lyalin's defection in 1971 opened the eyes -- very wide too in astonishment -- to the British authorities of how many Russian spies were working under different guises in the UK. That is separate from the rather amateur home-grown bunch Lyalin's predecessor had ensnared in the UK.
Some interesting details outside of that is Edward Heath having the courage to tell 'Tricky Dickie' Nixon he preferred to alter the term special relationship (imho an appalling phrase) to a natural relationship. It certainly played well with the audience Heath wished to reach, the European Community as it was called then. However, this natural relationship did not extend to Heath informing Nixon of the mass expulsions of spies (105) until it was done and dusted.
A big reason for this was the brooding presence of the paranoid CIA Counter-Intelligence chief James Angleton, who like many had been duped by his close friend Kim Philby. It has often surprised me quite why Angleton is revered or indeed succeeded in climbing to such a position in the intelligence service. His list of achievements as far as I can see reads as zero, his paranoia created unnecessary witch hunts within the CIA, ruining several careers for no reason, and in MI5 unwarranted accusations levelled at Sir Roger Hollis and his deputy of being Soviet spies -- which for a time were pursued by the former's successor Martin Furnival Jones.
All this is covered in this terrific book. Indeed whilst mud was flung at any 'walk-in' defector by Angleton and his very own 'walk-in' defector Anatoliy Golytsin and indeed unjustifiably destroyed the credibility of several of them, it is interesting Furnival Jones withheld Lyalin's defection till after the fact. Even he had become wary of the double act over at Langley.
One has to wonder whether Angleton himself was not the high-placed double agent -- Golitsyn his Mephistopheles -- given his total lack of success in his own role, but expert at creating chaos all round him in their allies intelligence agencies.
I guess we will never know the answer to that but we can thank MI5 and Lyalin for making the UK a safer place -- no assassinations nor sabotage for decades in Britain until Putin came to power.
He and his mistress Irena Teplyakova, married to a colleague of Lyalin's, sacrificed a lot in going over to the other side. Neither of them ever saw their respective son's again -- Lyalin's had been baptised Alexander, in honour of the agent's half-brother a Red Army soldier killed in World War II, a hefty price to pay especially for Irena, whose willingness to defect is open to question.
A cracking tale, pings along at Len Deighton pace rather than the more sedate one of Le Carre and equally as thrilling.
Chapeau sir.

[Kevin Riehle · Rating 3 out of 5]

Kerbaj starts with a story about KGB defector Oleg Lyalin, who offered himself to the UK government in 1971. He then weaves into it the story of another KGB defector from a decade earlier, Anatoliy Golitsyn. Kerbaj ends up spending much more time talking about Golitsyn than about Lyalin.

Kerbaj dismantles the Angleton/Golitsyn "Master Plot" conspiracy mindset. That is a welcome contribution. However, Kerbaj takes his argument a step further by claiming that Golitsyn and Angleton might have been Soviet penetrations, rather than Yuriy Nosenko. That is a step too far. While no one did more damage to the CIA's ability to operate against the Soviet Union than Angleton and Golitsyn did, that does not mean they did it on instructions from Moscow. They were more likely psychologically unfit for their jobs, not Moscow plants.

The predominance of material about Golitsyn looks like a substitute for the lack of material available about Lyalin. Lyalin's story is probably not sufficient to fill a whole book, so Kerbaj had to overlay his story with another one.

[Keelyn · Rating 4 out of 5]

Cold War era espionage is full of exciting stories and people, and the story of Oleg Lyalin definitely fits in that category, making The Defector a very exciting and engaging read.

Kerbaj did a wonderful job sharing his research of not only Lyalin, but others in the spy world in Moscow, Britain, and the USA, in a way that was interesting and understandable even for those who may have little to know previous knowledge of these events and people.

While the writing was easy to understand and get caught up in, I did have to start the audiobook over several times and eventually had to tandem read along side an ebook version of the book, because it was too hard to keep track of who was who just using the audiobook. This had nothing to do with the narrator - John Sackville's narration was very good - but simply a result of too many unfamiliar names and places that got tangled up without being able to see them on page.

I received an audio ARC of The Defector through NetGalley which I read and reviewed along side a purchased kindle version of the book.

[Adam Coombs · Rating 5 out of 5]

Review of advance copy received from Netgalley

One of the best Cold War non-fiction espionage books I have ever read. Kerbaj focuses on a few key characters, particularly that of Oleg Lyalin, a KGB sabateur operating undercover in London as a Soviet trade delegate, to tell the story of the British decision to expell hundreds of Soviet officials from the UK.

Lyalin himself is a fascinating character who chooses to defect to the UK for a variety of complex reasons, most of them personal. By focusing on one man, Kerbaj is able to explore his motivations and allow the reader to, as much as possible, enter Lyalin's world and understand his motivations and actions.

Kerbaj is also dedicated to his story and eschews any overt moral judgements of his subjects. He presents their story and allows the reader to decide who are the heroes and villains in the book. He rightly highlights the subjects acts of incompetence, cruelty, selflessness and delusion but never condemns or praises them for it. His trust in his reader is one of the best selling points of the book.

Perhaps mostly importantly, the book is exciting and engaging. For readers who love John LeCarre for his use of tradecraft terminology and an "insiders" view of Cold War espionage, this book will be a treat. Kerbaj discusses the way that Soviet intelligence agents operated, how they cultivated sources and the tradecraft involved in getting sensitive intelligence back to Moscow. Yet this level of detail never bogs down the narrative, instead it makes the story feel authentic and convincing.

For readers who loved Ben McIntyre's A Spy Among Friends and want a story of British intelligence success (that also features Philby) this book is highly recommended.

[Martin Lember · Rating 3 out of 5]

Having read several books about cold-war spy topic, this book was average. Suitable for topic fan, but generally not so easy flowing book to read.
Core of the book is focusing on how CIA and MI5 evaluated deflectors and how CIA boss J.J. Angleton had evaluated them almost in extreme, thinking they are all part of KGB plot. He was backed with Anatoli Golitõn - one of the first defectors who proved himself, although several suspicions were not removed on him either. The change came, when MI5 reevaluated their relations with CIA from special (always keep the look and ask advise) to transparent (need based info sharing) and when they dealt with KBG officers in mass in UK after Oleg Ljalin defected from the KGB to UK and shared the intel.
If you want a book about the same topic, can recommend "The Spy and the Traitor: The Greatest Espionage Story of the Cold War" for example.

[Moira Mackinnon · Rating 4 out of 5]

Really interesting read. I had a particular interest in the subject for several reasons: I was conceived while my parents were in Moscow, where my father was in charge of security at the Canadian Embassy; my godfather was the Canadian Ambassador John Watkins, who was later accused of being a Russian agent (wrongly, but he was targeted by them because of his homosexuality); and my father later worked keeping tabs on known Russian agents for the Canadian government for 6 years during the 1960s. So I knew some of the background, but still learned a lot. I found the book easy to follow and a fast read for such a complicated subject. Oddly, the print size was much larger than usual, and there were a few print errors (words in the wrong order and several words run together), but these were editing issues and didn't distract from the overall fascination of the subject.

[Nicola Waters · Rating 3 out of 5]

A good review but it’s very clear that the main focus of the book could have been covered in a long form article- to get book length it’s heavily padded, although the author ties it all to the main narrative well. But a lot of the information on e.g. James Angleton won’t be new to anyone with a modest interest in the subject matter. And the final claim that he may have been a soviet spy somewhat undercuts the author’s credibility. Angleton was a power-crazed loon (or at least, wildly psychologically unsuited to that line of work)- there’s no need to stretch for dramatic explanations of his behaviour. Some of which presumably came from embarrassment that his little drinking pal was in fact a Soviet spy.

[Elizabeth Coulter · Rating 5 out of 5]

I met the author a few weeks ago and heard him give a brilliant talk on the UK/Russia relationship, drawing on elements from this book. He took questions from the great and the good of the field - professors and diplomats etc - very well. As a result, I bought this book, motored through it and found it a very easy read, even for a layperson like me. I learnt a lot and now know the stories of Lyalin, Golitsyn, Angleton etc which is useful when reading other linked books including fiction like The Seventh Floor by David McCluskey which liberally sprinkles in references to these guys. I will be reading Kerbaj’s book on the history of the five eyes very soon!

[Perry Burton · Rating 2 out of 5]

I make a point of finishing every book I start. But that was pushed to the limit here as I skip read the last 80 pages. Maybe if I was alive at the time it would have been better (hence 2 stars rather then 1), but I found this book confusing and dull…I kept thinking it would improve but it never dead. Unless the story is of real interest to you I would avoid

[Julian Walker · Rating 4 out of 5]

A great insight into the Cold War which vividly brings to life the attitudes, fashion, and style of the times which provided a backdrop to an extraordinary true life spy story.

Highly readable and absorbing, I enjoyed this immensely.

[Jim Sullivan · Rating 3 out of 5]

This is an interesting look at Russian defectors during the cold war.

[Patrick Sullivan · Rating 4 out of 5]

Interesting.

[Brooks · Rating 3 out of 5]

The second half was better than the first half.

[Tom Bridgens · Rating 4 out of 5]

This is a good book. If you enjoy Ben Macintyre, this book is for you.