The British Secret Intelligence Service – popularly known as MI6 – is the oldest continuously surviving foreign intelligence-gathering organisation in the world. It was founded in October 1909 as the ‘Foreign Section’ of a new Secret Service Bureau, and over its first forty years grew from modest beginnings to a point in the early Cold War years when it had become a valued and permanent branch of the British state, established on a recognisably modern and professional basis. Although for most of this period SIS supervised British signals intelligence operations (most notably the Second World War triumphs at Bletchley Park over the German ‘Enigma’ cyphers), it is primarily a human intelligence agency. While this history traces the organisational development of SIS and its relations with government – essential aspects for an understanding of how and why it operated – its story is essentially one of people, from the brilliant and idiosyncratic first Chief, Mansfield Cumming, and his two successors, Hugh Sinclair and Stewart Menzies, to the staff of the organisation – men and women who served it across the world – and, not least, to its agents, at the sharp end of the work. It is impossible to generalise about this eclectic and cosmopolitan mix of many nationalities. They included aristocrats and factory workers, society ladies and bureaucrats, patriots and traitors. Among them were individuals of high courage, many of whom (especially during the two world wars) paid with their lives for the vital and hazardous intelligence work they did.

SIS did not emerge from a complete intelligence vacuum. For centuries British governments had covertly gathered information on an ad-hoc basis. In the seventeenth century successive English Secretaries of State assembled networks of spies when the country was particularly threatened, and from its establishment in 1782 the Foreign Office, using funding from what became known as the ‘Secret Service Vote’ or the ‘Secret Vote’, annually approved by parliament, employed a variety of clandestine means to acquire information and warning about Britain’s enemies. By the end of the nineteenth century the army and the navy, too, had intelligence-gathering branches, which processed much information acquired relatively openly by naval and military attachés posted to foreign countries. But, after the turn of the twentieth century, with foreign rivals (Germany in particular) posing a growing challenge to national interests, British policy-makers began to look beyond these unsystematic and uncoordinated methods, and, as the Foreign Office worried about the possibility of its diplomatic and consular representatives becoming caught up in (and inevitably embarrassed by) intelligence-gathering, the notion of establishing a dedicated, covert and, above all, deniable agency came to find favour.

The Secret Service Bureau, and the subsequent Secret Intelligence Service, remained publicly unacknowledged by the British government for over eighty years and was given a formal legal basis only by the Intelligence Services Act of 1994. Th e fact that a publicly available history of any sort has been commissioned, let alone one written by an independent professional historian, is an astounding development, bearing in mind the historic British legacy of secrecy and public silence about intelligence matters. It is also an extraordinary once-in-a-lifetime opportunity (and privilege) to be appointed to write this history, though I am well aware that the fact that I have been deemed suitable to undertake it may in some eyes precisely render me unsuitable to produce an independent account of SIS’s history. But of that the reader must judge.

Part of the agreement made on my appointment was that I should have utterly unrestricted access to the Service archives over its first forty years. I am absolutely confident that this has been the case and it has been an unparalleled treat to be let loose in the archive, which is an immensely rich (though in places patchy) treasure-trove of historical materials. In addition to this access, I have also been allowed to read some post-1949 materials bearing on the history of the Service. In general, the SIS attitude to archives was that they should be kept only if they served some clear operational purpose. Certainly, since no one envisaged that a professional history of any sort would be written, let alone one that might be published, there was no imperative to retain materials for historical reasons. When the Service did begin to think historically, which, from the evidence I have seen, was not much before the 1960s, a huge amount of material had already been lost.

Within SIS the practice appears to have been routinely to destroy documents once their immediate relevance or utility had passed. There is plenty of internal evidence indicating this, some of which has occasionally slipped out into the public domain. In a 1935 letter to Valentine Vivian, head of the counter-espionage Section V in SIS, Oswald ‘Jasper’ Harker of MI5 remarked, ‘An old report of yours regarding a Madame Stahl has just come to light – I enclose a copy as I believe your 1920 records have been destroyed.’ Reviewing the work of SIS in the early 1920s, one officer observed that the SIS headquarters ‘receives from its overseas branches over 13,000 different reports per annum, exclusive of correspondence about these reports and administrative matters’. He noted that ‘the mass of papers involved immediately becomes apparent’. In order to keep the volume of material under control, he added that ‘every effort is made to destroy all matter … not needed for reference’. The practice of clearing out old papers has also been powerfully stimulated by the fact that the organisation has moved house on some six occasions during the last century.

Over the years some documents were recognised as having real historical significance and were preserved. One such is the ‘Bethell letter’, from the Director of Naval Intelligence to Mansfield Cumming on 10 August 1909 inviting him to become (as it turned out) the first Chief of the Service. There has, nevertheless, been intermittent, methodical and substantial destruction of records which may, or may not, have been of historical value. But I have found no evidence that the destruction was carried out casually or maliciously, as some sort of cover-up to hide embarrassing facts about SIS’s past or whatever. The destruction has resulted more from a cultural attitude where the retention of documents in general was assessed in the light of their current (and certainly not historical) value to the Service, primarily in operational terms.

The corollary to unrestricted access to the archives has been an extremely painstaking and fastidious disclosure process. From the start (and for obvious reasons) it was laid down that the identity of any agent could not be revealed for the first time in this book. One result of this stipulation is the regrettable need (from the historian’s point of view) to omit some significant and important SIS stories, as it would not be possible to include them without providing at least circumstantial details which could potentially help identify agents. Exceptionally, however, some agents’ names do appear in the book, but each case has been subject to the most careful and rigorous disclosure criteria. Where agents have clearly named themselves (not uncommon for individuals who worked during the world wars), this has been relatively straightforward, but simply arguing that an agent’s name is ‘in the public domain’ is not in itself sufficient, as the ‘public domain’ constitutes a great range of contexts, from unsubstantiated assertions in sensationalist and evanescent publications (what might be called ‘sub-prime intelligence literature’) to serious and scholarly articles by professional historians.

What remains? Quite a lot, despite the fact that immense quantities of documents were destroyed, especially during the period covering the headquarters move from Broadway to Century House in the early 1960s.  The first thing to be said, however, is that (perhaps surprisingly) the archive contains comparatively little actual intelligence. Over the 1909–49 period with which I am concerned SIS was always primarily a collection agency, responding to specific or general requests for information from customer departments, principally its parent department, the Foreign Office, and the armed service ministries. The information requested (if available) was collected and passed on to the relevant department. Little or no analysis was applied to this material within SIS, apart from some outline indication about the reliability, or otherwise, of the source. Once the raw material was passed on to the user department, they processed it and normally destroyed the original documents. Intelligence assessments were the job of the particular desk in the Foreign Office, the Directorate of Military Intelligence and so on, not of SIS.

SIS’s deployment and work, therefore, was principally defined by the priorities and perceptions of external agencies. Between the wars Soviet Communism remained the chief target, and a particular concern with naval matters in the Mediterranean and Far East clearly reflected Admiralty perceptions and intelligence requirements. During the early and mid-1930s SIS resources, in any case constrained by an acute shortage of funding, were not focused on the developing challenge of Nazi Germany as much as (admittedly with the benefit of hindsight) they might have been. Although the Service was, nevertheless, quick off the mark to report German rearmament, there was evidently little demand in London for secret intelligence about internal German political developments. There is, for example, almost nothing in the SIS archives (both for this period and during the Second World War) about the persecution of Jews generally or the Final Solution. A report from Switzerland in January 1939 is a rare exception. An SIS representative had asked an Austrian- Jewish refugee if he could supply ‘any information about people in concentration camps’. The source said that he knew a man in Geneva who had spent nine months in Dachau, ‘but he doubted whether he could get this man to talk. He said German refugees were frightened of saying anything against Germany, because European countries were riddled with Nazi agents and they feared reprisals.’

One of the things I had hoped to do in this history was find instances when I could track the process from the acquisition of a specific piece of intelligence to its actual use, but in the absence of much of the raw material I have found this quite difficult (though in some cases not impossible) to achieve. I might remark that the situation is quite different with regard to signals intelligence where a considerable volume of the raw (or rawish) product survives and can readily be used, as in Sir Harry Hinsley’s magisterial volumes, to estimate ‘its influence on strategy and operations’, as his sub-title promises. During the First World War, nevertheless, I have for example been able to trace the use of human intelligence from the ‘Dame Blanche’ organisation in occupied Belgium, as well as the ready and informative response of the German naval spy TR/16 to requests for details of German losses in the Battle of Jutland in 1916. In the mid-1930s (though it was not always taken as seriously as it should have been) SIS reporting was used to inform British assessments of German rearmament. In the Second World War, specific SIS intelligence underpinned the important Bruneval raid in February 1942 and provided early indications of the German V-weapons development programme.

But, on the whole, the story of human intelligence is not generally one of fiendishly clever master-spies, or Mata-Hari-like seductresses (though in this volume the keen-eyed reader will find one or two possible examples of these types), achieving fantastic, war-winning intelligence coups. It is more like a pointillist painting, containing tiny fragments of information, gathered by many thousands of individual men and women in circumstances fraught with danger, which need to be collected together to provide the big picture. Watchers along the Norwegian coast in the Second World War, for example, provided precious information about enemy ship movements. These individuals had to get to what were inevitably exposed situations; once there they had not only to collect their intelligence unobserved, but also to communicate it quickly back to London; and at each stage of the process the penalty for discovery was almost certain death. In both world wars, ordinary men and women in enemy-occupied Europe ran similar risks, for example train-watching, carefully logging the movements of railway trains and their cargoes and endeavouring to identify the military units they carried. We ought not to pass over in silence the astonishingly brave actions of these numberless, and for the most part nameless, people, few of whom were the kind of spies so beloved of film and fiction, but many of whom contributed to the successes of British intelligence during the first half of the twentieth century.

The material which survives in the SIS archive is more abundant on the process and administration of acquiring intelligence than on the intelligence itself. ‘Sources and methods’, the most sensitive of all aspects of intelligence work, are embedded in this material: names of officers, agents, sources, helpers, organisations, commercial companies, operational techniques, various sorts of technical expertise and the rest. While some of these no longer pose any security risk – for example there seems little danger that national security may now be jeopardised by revealing 1940s wireless technology – documents relating to agents and their activities have the potential to jeopardise them and their families even long after they may have ceased working for SIS. A typical agent file, for instance, may, without giving very much detail, note that she (or he) produced ‘much valuable intelligence’. The  bulk of the documents may thereafter contain details for years afterwards of the agent’s address (say in some foreign city), pension payments and perhaps reports of visits by an SIS welfare officer, bearing a Christmas bottle of whisky or some other suitable gift. This is exactly the kind of material which the Service rightly believes can never be released.

This history, written as it were from headquarters, reflects the surviving SIS documentation upon which it is primarily based. This means that it has sometimes been difficult to recreate the personal relationships between case-officers and agents which lie at the heart of human intelligence work. Busy case-officers did not often have the time to write reflective notes on their agents’ personalities or motivations, though some hints of these fascinating matters have, happily, survived, and are included in my narrative. I have in general used memoir material very sparingly. Although often revealing on the personal side, the recollection of events and emotions, sometimes many years after, presents critical problems of interpretation and assessment for the historian, particularly in the matter of espionage and other covert activities, which are not infrequently cloaked about with a melodramatic air of secrecy, conspiracy, conjecture and invention. This is not to say that such things do not exist – indeed examples of each might be found in this book – and I have drawn on secondary sources in cases where they seem to be particularly illuminating. Nevertheless, my primary objective has been to base the narrative as closely as possible on the surviving contemporaneous documentary record. If this approach risks some loss of vividness, then it does so expressly for the purposes of historical accuracy.

As will be apparent from the reference notes, I have also had privileged access to relevant but closed documents held by other British government departments. These have been especially useful in helping place SIS in its wider bureaucratic context. With a very small number of exceptions, all other primary source materials (including some extremely valuable sources in foreign archives) are fully open to the public.

Quotations from documents in closed and open archives are reproduced exactly as originally written with the following exceptions: proper names rendered in most official papers in block capitals have been given in title case, with agent and operation code-names in quotation marks; numbering or lettering of individual paragraphs in cables and other documents has not been reproduced; in communications where names of people, places and organisations were given letter codes (‘A’, ‘B’, ‘C’ and so on), the key being transmitted separately, the correct name has been substituted for the code-letter. Queried words in deciphered messages are as in the original (for example, ‘reliable’). In a few cases punctuation has been silently adjusted for the sake of clarity. Since records from the SIS archive are not released into the public domain, no individual source references are provided to them. In this case I have followed the precedent set by past British official histories. Calculations of current value of historical sums of money are based on the Retail Price Index, as indicated in, which has also been used for exchange-rate information.

This account of SIS’s history finishes in 1949, at a moment when the Service had moved from being a tiny, one-man outfit to a recognisably modern and professional organisation. After forty years’ existence, SIS was on the threshold of four decades when the Cold War challenge of Soviet Communism would dominate its activities. But these are matters which I leave to my successor, if there is one.

You are the first independent historian who has ever been allowed inside the MI6 archives, how were you chosen for the task?

The procedure was part-head-hunt and part conventional job-application. I’ve been working on aspects of military and intelligence history for nearly 30 years and was just completing a biography of Field Marshal Sir Henry Wilson, a flamboyant and controversial First World War general who was (among other things) head of British Military Intelligence before 1914, when I was asked if I might be interested in ‘doing something historical’ to mark the centenary of the foundation of the Secret Intelligence Service (or MI6, as it is popularly known). Since I was assured that this would involve privileged access to the secret SIS archive, the offer was too attractive to refuse. I was not the only person sounded out, and, after I had been asked to prepare a scheme for a history of SIS’s first 40 years—from 1909 to 1949—which passed some sort of test, the process developed into a job-interview situation. I was not the only person interviewed, but, again, I passed the test and was offered the commission.

What was it like being inside archives that may never see the light of day again?

The SIS archive is the Holy Grail of British government records. None of SIS’s own papers are released to the National Archives, nor is it envisaged that any will ever be so released. The whole lot are also completely exempt from UK Freedom of Information legislation. As a result, when I actually got access to the papers, it was like being a kid in a candy store. The records themselves are not physically very different from other government documents of a similar age. I’ve been working for years in national and other archives—including, for example, the US archives at College Park Maryland—with ‘Top Secret’ military, political and intelligence papers, and the SIS papers are very similar in type. But there is obviously a tremendous thrill in being an outsider seeing classified materials for the first time. I was also acutely aware that there were (and are) no plans to let any other historian into the archive, and that I had only this one go at writing the history, so I had to get it right first time—or as right as possible. So, no pressure there!

Did you discover anything that shocked you?

What shocked me most of all was the sheer human cost of intelligence work. Working undercover and having to keep secrets for all of one’s life, while doing sometimes extremely hazardous work, is immensely hard. In wartime especially, many officers and agents paid with their lives. Of course we know intellectually that war is dangerous, and that people die. But when you find yet another agent ‘murdered at Buchenwald’ (for example), or stumble on the grainy individual circumstances of real people’s deaths captured in the apparently dryasdust documents on your desk, it gives one pause, and made me reflect (as it must anyone) on what I might have done in such circumstances.

What are the revelations in your book?

The chief revelation of the book is, in fact, the book itself, and the utterly counter-intuitive action of the most secret department of the British government actually commissioning a history for open publication, to be written by an independent professional historian. Of course, for the very first time, the structure and organisation of the agency, and its development over the first 40 years of its life, is reliably and authoritatively laid out. For the first time, too, the names of over 150 officers are named with the authority of the Service itself. But the history is also ‘warts and all’; failures are faced as well as successes.

There are never-before-told operations which include SIS work against the USA between the wars, focusing on American naval and military targets (the Royal Navy was, for example, particularly anxious to know about US naval construction), as well as American left-wing political groups and Irish nationalists. There is much detail about work against Soviet Russia in the post-revolutionary period, including operations in Romania in the 1930s, where the SIS head of station’s over-trusting attitude led to the loss of agents working in the Soviet Union, and also in Bulgaria, where the head of station got into trouble over money. Details of  SIS operations in Latin America in the Second World War have never before been told, including ship-watching for German commerce raiders; a telephone-tapping operation working from the basement of the Santiago embassy; tracking down of Nazi agents across the continent; and unsatisfactory agents (among whom were a French morphine addict and a ‘Chillian Irishman’). The book contains detailed coverage of the Service’s most successful interwar agent, Jonny de Graff, a Comintern officer who came over to SIS in 1933 and supplied a wealth of information about Soviet activities in Britain and across the world, as well as helping to foil a leftwing revolution in Brazil in 1935.

One of the most sensational stories in the book covers ‘Operation Embarrass’ and is as close as you’ll ever get in real life to an espionage thriller. Occurring in 1947–8, it was aimed to disrupt illegal Jewish emigration into Palestine and included direct action with limpet mines to disable potential refugee ships in port (including the vessel which became the famous Exodus); a black propaganda campaign from a bogus Arab organisation, among other thing sending forged letters to the British Prime Minister and Foreign Secretary; and planting disinformation documents on Soviets in a Vienna night club.

Another operation with the air of a thriller was ‘Climber’ in 1948–9 to penetrate the Soviet Union across the Caucasus mountains, but it also illustrates how human frailty could bring serious risks. The Georgian agents jeopardised security by returning to London ‘with their suitcases bulging with every sort of Turkish delicacy’ and ‘a large number of female garments which they were conveying from mutual friends’ in Istanbul for émigrés in Paris. We presume the famous traitor Kim Philby, then Head of Station at Istanbul, also betrayed the operation.

What espionage techniques did you discover which surprised you?

I was intrigued (as was the Service Chief, Mansfield Cumming) by the discovery during the First World War that semen made a usable secret ink for invisible writing. Apparently the SIS representative in Copenhagen stocked the substance in a bottle ‘for his letters stank to high heaven’, and he had to be told that ‘a fresh operation’ was necessary for each message. I was also impressed by the ingenuity displayed in concealing devices, to smuggle sensitive documents or other materials past security checkpoints. It was reported that in Italy during the Second World War a false horse penis had been manufactured and used.

Who is your favourite person in the book and why?

It has to be the first Chief, Mansfield Cumming, without whom the Service would not exist today. From a standing start in October 1909, he created an impressively functioning organisation which made a significant contribution to Allied intelligence work during the First World War. He fell in love with the ‘business’ of espionage—what came to be known as ‘tradecraft’—secrecy, disguises, cutting-edge technology and so on. He was also stoical and brave and was the subject of many extraordinary stories, including that he cut off his own leg with a penknife after a motor accident in 1914 which left his only son fatally injured. He was clearly a most attractive personality, much loved by his staff, though he was not without frailties, which included a keen eye for the ladies and a penchant for Edwardian pornography.

What was the most interesting thing you unearthed about a well known character?

That the novelist Graham Greene, recruited in the summer of 1941 to work for SIS in West Africa with cover as an army officer, was so physically incompetent and unco-ordinated that he had to be sent to a military training course in Oxford solely to be ‘given the most elementary instruction in soldiering’, in order to ‘wear battledress without embarrassment’.

Who was the most interesting new figure uncovered?

There are so many, but one of the best was agent ‘Ecclesiastic’, a glamorous 22-year-old Central European woman living in Lisbon, where she was the mistress of a German Abwehr (Military Intelligence) officer. Taken on by SIS, she became a double-agent, feeding carefully-collated disinformation to the Germans. This successful operation is unusually well recorded, including revealing reports from her flirtatious case-office, ‘Klop’ Ustinov (father of the actor Peter Ustinov), as well as a unique image of Ecclesiastic at work taking photographs of documents which she had purportedly taken from the Anglo-Portuguese Air Liaison office where she worked. Her German lover took the photograph as insurance against Ecclesiastic betraying him, and gave her a copy to confirm his hold over her. But she promptly passed it on to  her case officer and it survives in the SIS archive to this day.

The world’s most famous MI6 operative, albeit fictional, is James Bond. How does the real work of MI6 compare to that depicted by Ian Fleming?

The real work of MI6 is much more interesting, and much more grimly realistic than the fictional. James Bond is terrific entertainment (or at least the best movies are), but, in the end, he is not much more than a kind of cartoon character, who manages ‘with one bound’ (or so) to get free from the clutches of whatever evil genius he has taken on. Since the real James Bonds are real people, they do not have quite the indiarubber qualities of the fictional one. When they are knocked down they sometimes, alas, stay down. They are, moreover, frequently better trained and prepared than Ian Fleming’s fictional creation, who, for example, does not appear to speak any language other than English (though, arguably, Sean Connery can speak Scottish). But one of the prerequisites for a genuine MI6 officer is a facility with languages. Ian Fleming, who worked in British Naval Intelligence during the Second World War clearly knew a lot about intelligence work and people, and there are suggestions that James Bond might in part have been modeled on a debonair SIS officer called Biffy Dunderdale, who was Head of the SIS Station in Paris during the 1930s. Some other stories seem familiar from the Bond oeuvre, for example, the Dutch agent put ashore in November 1940 on the beach near the Casino at Scheveningen, wearing a tuxedo protected by a specially-designed rubber oversuit. To strengthen his party-goer’s image, his minders sprinkled some drops of Hennessy XO brandy on him before setting him ashore.

There is an enduring fascination with intelligence work. How do the actions of 1909–49 relate to modern intelligence?

There are obvious differences between today’s intelligence environment and that of sixty years ago and before, with technology perhaps being the greatest change, but the essentials of successful intelligence work are amply demonstrated in the 1909–49 history of SIS. At the heart of all intelligence work is trust, not just between case officers and their agents, but also between the agency and its government masters. This is as true of 2011 as of 1911. There were moments in the 1920s and 1930s when SIS, under the ambitious and empire-building leadership of Admiral Hugh Sinclair, got a bit ‘big for its boots’, trespassing, for example, into domestic security work for which it was ill-suited and which dangerously threatened to jeopardise its reputation.

From the very start, Mansfield Cumming recognised the varying motivations of agents: money, patriotism, ideology, revenge. Not much changes in this world. Another constant is the important subject of liaison with foreign security and intelligence agencies. SIS has had to cosy up to potential rival organisations—French Intelligence in the 1920s; the Gestapo in the 1930s—in order to target common enemies—the Italians and Communists in the two examples just cited. Spying against friends and/or potential allies can be problematic, as demonstrated with British operations against the USA in the 1930s. In this case, friendly co-operation and the abandoning of those operations (though not before they had systematically been evaluated) proved to be more productive than keeping them on. One difficulty with a distinctly modern resonance is the experience of the SIS officer who visited Palestine in December 1939. Here the British administration of the territory told him they wanted information about the Jewish Agency, and especially about their support of illegal Jewish immigration. The next day, a contact in the Jewish Agency, in turn, offered their assistance in intelligence-gathering.

Another dimension with a remarkably contemporary feel is the assessment of potential bio-warfare threats to London drawn up by an SIS committee in August 1939. Reflecting on the possibility of anthrax or foot-and-mouth disease attacks on agricultural targets, it also asked if ‘one hundred Nazi agents supplied with bacteriological material and operating in the London Underground Railways during the rush hours, [could] start a serious epidemic in London’. Even on the technology side, many of the changes are purely of scale rather than kind. The pioneering portable suitcase radio developed by SIS’s engineers during the late 1930s is the Second World War equivalent of today’s cell phone, and the careful protocols for using those wartime radios securely remind us, today as much as ever, that any method of communication is liable to be vulnerable if not properly used.

Did you have to leave a lot out of your book at the request of MI6?

This is a really important question, since it reflects on my status as an independent historian. While I was granted complete and free access to the SIS archives for the period of the book (and this was a potential deal-breaker if I had found my access in any way restricted), and that the history should be ‘warts and all’, the corollary to this was that my final text would be reviewed in-house for what were described as ‘necessary national security requirements’. The most significant dimension of this concerned the naming of agents. SIS’s line, which I accepted, is that it will itself never reveal the name of an agent. In general, only if an agent has ‘outed’ him- or herself, can their name be revealed. This point of principle obviously makes very good sense, and goes to the heart of the relationship of trust between the Service and its agents. If, for example, you are a German hired by the British to spy against Nazi Germany in the 1930s, SIS will say: ‘Your secret is safe with us, in perpetuity’. (One analogy is with an investigative journalist, who may go to jail before revealing his sources.) But after 1945, for example, that German agent might be very glad to have her story told, and may even publish memoirs revealing this. In that case, and in some other cases where the identity of an agent is authoritatively revealed in publicly-available official documents in an archive or museum, I was permitted to name names. Even in those cases where I couldn’t reveal names, I could still tell the stories using cover-names or numbers (which is, after all, what cover-names are for).

There still remains the reasonable suspicion on the part of skeptics that I, having been found suitable by SIS to write its history, might be precisely the wrong person to do an independent and properly-critical job. All I can say to that, is (a) the opportunity (of a lifetime) to be the only historian allowed access to the SIS archives was too great to resist; (b) even if it might be seen as a kind of Faustian Pact with an immensely powerful and seductive organisation, the risk was worth taking; (c) as a senior academic historian with a high reputation to protect, and much to lose if I did only a partial job, I hope my professionalism has enabled me to get the story as right as possible; (d) in practice, while I was prevented from including some details of names etc, I was not restricted from including material about bungled operations and inadequate personnel which was not to the credit of SIS; and (e) in the last resort the ‘proof of the pudding [etc]’ will lie in the text itself, and for that the discerning reader must make up his or her own mind.

What do you think is the enduring importance of your work?

My book has been called ‘definitive’, a flattering description but one with which I have some worries. Whether it is already definitive or not, I very much hope that the book becomes definitive, and really only time will tell, as it might take five or ten years for this to be so. The book certainly has been written to stand the test of time. It is authoritative, and, since it is the only work based on access to the SIS archives, will, at the very least and for many years to come (if not for ever), remain the only reliable source for the real story of SIS. If it becomes definitive, I shall be well content. Like any author, my chief hope is that the book will be widely read and bring pleasure as well as conveying information. In the meantime, however, it is an indispensable source for anyone interested in ‘grown-up’ history, particularly that of the most famous intelligence organisation in the world.