Klop’s introduction to MI5 put him in the position of answering to two masters. Vansittart at the Foreign Office still wanted to know what was going on in Germany; Liddell was concerned with counter-espionage on the home front. But there were no hard and fast demarcation lines. When Liddell recruited Dick White to MI5 in 1936 his first act was to send his future deputy on a tour of Germany to improve his language skills and familiarise himself with the Nazi regime.

On his return he became Klop’s case officer and, as he later told his biographer:

Here without question we had picked a natural winner who would not let us down … the best and most ingenious operator I had the honour to work with.

Klop and White also shared a certain disdain for some of the old-fashioned MI6 officers whom they encountered and who appeared to be ‘ivory from the neck up’.107

White had been assigned to fill the void of MI5’s ignorance about German intelligence activities in Britain and was coached by Klop and Putlitz, who also introduced him to Vansittart’s private intelligence system. Thereafter White often served as a staging post at which high-ranking anti-Nazi visitors from Germany could stop off to deliver their warning messages for Vansittart.

Although Klop was by now an employee, albeit a part-time one working at arm’s length, he was rarely referred to by name but by his soubriquet U35. The U might almost stand for ubiquitous – it appears in the MI5 wartime records and those of the Foreign Office in a way that no other agent does. But it is a curious choice. Taken at face value it could be short for Ustinov 1935, the year he was recruited. That seems too transparent to be true, and he had in any case been unofficially recruited some time earlier. It is also out of keeping with normal practice. MI5 rarely gave its officers a cover name consisting of initial and numbers. They were more likely to use a pseudonym. MI6 did use initials and numbers in the 1920s but had largely abandoned the practice by the 1930s, preferring a five-digit code in which the first two digits signified the country of operation.

There is, however, a curious anecdote about U35 which, if connected, would indicate an unsuspected sense of humour among the heads of the intelligence services. It concerns Admiral Wilhelm Canaris, who became head of the Abwehr, German military intelligence, on his forty-seventh birthday, 1 January 1934.

He was small, shrewd and secretive, fluent in English, French and Russian, educated, well-travelled and an officer of the old school. He despised Hitler and it is now generally accepted that, while he performed his duties effectively enough to remain in office until 1943, he was throughout working in what he believed were Germany’s best interests, not the Führer’s. At times that meant lending active assistance to the Western Allies. He stood back from the conspiracies to depose Hitler, while doing nothing to discourage his deputy Hans Oster from playing a leading role, and both men were executed after the assassination attempt on Hitler in July 1944. The Nazis condemned him as a traitor.

During the First World War he was an intelligence officer in neutral Spain where his reports enabled U-boats to wreak havoc on Allied shipping in the Mediterranean. Such was his notoriety that a young British intelligence officer, Captain Stewart Menzies, was sent to kill or capture him. More than twenty years later Menzies would become head of MI6, once more in direct opposition to Canaris. But it was the German who won that first encounter. Knowing that the British were on his trail, and despite two French submarines patrolling the coast, he took refuge in a small boat among the Spanish fishing fleet in Salitrona Bay near Cartagena, southern Spain. Germany’s most successful U-boat commander Lothar von Arnauld de la Perière slipped in unnoticed to rescue him. His vessel was U-35.108

On 7 March 1936 Hitler reoccupied the Rhineland. Vansittart’s assistant Ralph Wigram was given the task of escorting the French Foreign Minister Pierre Flandin to London where he tried without success to persuade the Prime Minister, Stanley Baldwin, to take a robust stance against the aggression. A sympathetic Wigram arranged meetings with every influential person he could find, including Churchill, but as it became clear Britain was neither inclined nor prepared for a confrontation, the despondent official told his wife:

War is now inevitable, and it will be the most terrible war there has ever been. All my work these many years has been no use … I have failed to make people here realise what is at stake.109

Before the year was out he died of cancer. On 31 December 1936, Vansittart wrote a memorandum entitled ‘The World Situation and British Rearmament’, in which he observed: ‘Time is vital and we have started late. Time is the material commodity the Foreign Office has to buy. Our aim must be to stabilise the situation till 1939.’110

This was the strategy which in part influenced Chamberlain’s ultimately fruitless endeavour to find solutions to Germany’s grievances. Even officials who no longer believed that such a policy could appease Hitler found it difficult, given Britain’s lamentable strategic position, to recommend alternative courses.

Around this time Klop also had the opportunity to enter a rather different, risqué artistic clique. It came about through his intimate relationship with the photographer Thea Struve which had threatened to drive a wedge between him and Nadia. When Nadia and Klop lived at 72 Lexham Gardens, Kensington in the early 1930s, Thea had been a near neighbour at No. 64, a house occupied by a coterie of respectable individuals among then Etheldred Browning, founder of a housing association for single women, the religious writer Arthur Howell Smith and Nadia’s fellow artist Vere Lucy Temple. Thea was, like Klop, a German exile. She had taken pictures at Marie Rambert’s Notting Hill theatre where Nadia designed the sets.

Nadia recognised that Thea was attractive in a rather special way. Her elongated figure reminded Nadia of a Modigliani or El Greco painting. She was broad-minded and unpredictable which made her intriguing to Klop and infuriating to Nadia, who admitted to powerful feelings of jealousy as she was obliged to witness their exchanges of sexual banter. As ever, she later tried to make light of it, recalling a wild Bohemian party in Bloomsbury when the lights went out. Klop had taken the opportunity to surreptitiously fondle his latest amour in the darkness, only to discover when the lighting was restored that he had missed his target and was greeted by the loving glance of a bearded Hampstead poet.111

It was in this Hampstead world, populated by a number of German cultural exiles, that Thea’s ambitions lay. She began photographing the sculptor Jacob Epstein and the surrealist painter Sir Roland Penrose at work in their studios. Penrose, friend and biographer of Pablo Picasso, and a Communist sympathiser, lived at 21 Downshire Hill and was a notorious party-giver. Many of the guests would have been of interest to Klop as would his neighbours in the Isokon building, better known now as the Lawn Road flats where some of the KGB’s best agents made their homes.

Thea moved in with Penrose and is believed to have been the model for one of his nudes, but it was to be a short-lived affair. He was already involved with the American photographer Lee Miller, who would become famous later as a Vogue war photographer and come under Klop’s scrutiny because of her Communist activities. She was married to an Egyptian diplomat and when she returned briefly to him Penrose wrote to her that Thea was now occupying his bed but added:

Thea left Penrose in December 1938 to start a new career at the Buchholz Gallery in New York, an occupation which would be of interest to Klop during his wartime duties in Lisbon.

In April 1937 Klop and Wolfgang zu Putlitz were involved in the expulsion of the German spy Otto Ludwig who was caught during a Customs search at Harwich carrying blueprints for a new type of armour-piercing bullet. As head of the consular department at the German embassy, Putlitz was responsible for looking after Ludwig’s interests while he was in custody. Simultaneously he briefed Klop on every legal move and contact that Ludwig made.

Klop was able to report that Ludwig’s first instinct was to ask Ambassador Joachim von Ribbentrop to intervene. Instead, Putlitz sent his assistant to interview Ludwig, who was anxious to warn his contacts in Britain to lie low. One of these was the German journalist Franz Wrede, who had been asked to establish contacts with Oswald Mosley, leader of the British Union of Fascists, and evaluate the group’s attitude to Hitler. Wrede’s colleague, Werner von Crome, was supposed to find out what were the prospects of Edward VIII being able to return to the throne. Edward had abdicated the previous year, over his determination to marry the divorcee Wallis Simpson, and was considered to be sympathetic to the Nazi regime. Later that year he paid a controversial visit to Germany and met Hitler. Karl Friedrich Basedow had posed as a British tourist and managed to get on board a British warship in Majorca to question the crew. He tried a similar stunt at the naval dockyard in Gibraltar.

Klop, playing the sympathetic fellow journalist, was able to chat to Ludwig’s colleagues about their plight and to feed back to MI5 the consternation that his arrest had caused in the German embassy and in Berlin. Klop went through Ludwig’s papers and diaries and concluded that he was an agent of the Gestapo who intended to set up a secret political intelligence unit to operate in peace and wartime. His notebooks revealed that among the tasks Ludwig had been set was to find out what Klop had been up to since he left the German embassy. Unfortunately, the spy charge would not stick because it turned out that the blueprint was the property of a foreign inventor who had already offered it to the British government and been rejected. Sir Robert Vansittart reported Klop’s findings to the Prime Minister who authorised the Home Office to expel Ludwig along with seven German journalists. Ludwig was convinced he had been betrayed – how else did Customs know to search him? – and was also incensed that Putlitz had treated him in such heavy-handed fashion. Putlitz was summoned back to Berlin to explain himself, particularly his very public remarks that Ludwig had behaved like ‘a complete fool’. Luckily for him, his outspokenness diverted attention from the possibility that he was the mole who had given away Ludwig’s mission in the first place.113

Wolfgang Gans Edler Herr zu Putlitz was a member of a Junker family – Prussian landed gentry – born in 1899 at Laaske in the Brandenburg province. His ancestors had been rulers in the Middle Ages until they were supplanted by the Hohenzollerns who eventually ruled the German empire until 1918. The Gans in the middle of his name means goose – the family estate was famous for them. After service in a Prussian cavalry regiment on the Eastern Front and Finland in the First World War, he had forsaken the family estates at Putlitz, midway between Berlin and Hamburg, for a university education and a career in the diplomatic service. Even in those days he had a reputation for left-wing sympathies and had supported the Communist-inspired revolution of 1918‑19 which led to the replacement of the imperial government with the Weimar republic. He was nicknamed das rote puttchen – the little red chicken – in a derisive reference to the traditional family association with geese. He had a letter of introduction to Klop and got to know him and Albrecht Bernstorff in London in the 1920s, while broadening his education with a spell at Oxford University. At Oxford he was befriended by Claud Cockburn and their paths later crossed in Washington, Berlin and back in London where Cockburn’s scurrilous newsletter The Week acquired an influence way beyond its meagre circulation and despite its editor’s unwavering commitment to Communism.114

In the late 1920s, when Cockburn worked for The Times in Berlin, Putlitz had been his best source in the German Foreign Office and they met again a couple of years later when both were posted to Washington. Cockburn recalled him as a big man, with gleaming grey eyes and a face like a hooded eagle. He occasionally thought wistfully that he might have been Germany’s ruler had his ancestors anticipated, as the Hohenzollerns had, how useful gunpowder could be in wartime. He was prone to moods of profound Prussian doom and occasionally envisaged himself leading his country away from the abyss towards which Hitler was leading them. In anticipation, he practised carrying large amounts of gold around in a body belt and concealed elsewhere about his person. It did not take Cockburn long to realise that Putlitz had no interest in women and preferred the company of young men whom he met in bars or in servants quarters. He scandalised the American diplomatic circuit by having an affair with the French ambassador’s valet.115

Putlitz was well connected. He was already friends with Franz von Papen, son of the former German Chancellor, and when he returned to work in London in 1934 he was greeted by the ambassador, Konstantin von Neurath, an old family friend who became Hitler’s Foreign Minister until 1938. He was in touch with ‘Putzi’ Hanfstaengl, who at that time was the Führer’s confidante.116 Claud Cockburn did him no favours though by reporting in The Week an incident in which Putlitz had posed as an American journalist for an interview with Joseph Goebbels. It had backfired, convincing no one and making Hitler’s Propaganda Minister look rather foolish.117

Klop initiated him into the mysteries of Fleet Street and introduced him to Sir Robert Vansittart. When Putlitz came under pressure to join the Nazi Party, Klop persuaded him to comply so that he could fight the regime from the inside. He was promised a safe haven in Britain if he was caught. He was remarkably productive; it was Putlitz who urged MI5 not to accept the appointment of Otto Bene as consul general because of his thuggish Nazi attitudes. He briefed them on social connections between the German ambassador Leopold von Hoesch and King Edward VIII’s mistress Wallis Simpson. When Hoesch died, to be replaced by Joachim von Ribbentrop, Putlitz explained that he had ordered the German press to avoid mentioning the King’s affair because he thought he would retain the throne and be sympathetic to Germany. The abdication came as a shock to the inexperienced diplomat – nicknamed Herr Brickendrop by the British press – and took some explaining to Hitler. At that time some German military leaders were trying to persuade Hitler to attack Russia, rather than Western Europe, confident that Britain would not come to the Soviets’ aid. As Ribbentrop’s attitude changed to one of hatred for the British, Putlitz kept Vansittart fully briefed. He tipped off immigration authorities about intensifying attempts by German agents to infiltrate Britain; throughout the first half of 1938 he warned of the increasing bellicosity of Hitler; and he predicted the invasion of Czechoslovakia. His message, repeatedly passed on by Vansittart, was that Britain was letting all its trump cards fall from its hand.118

Putlitz cannot have been an easy agent to run. He was actively homosexual and found his way into an Establishment network that brought him into dangerous company, in particular Guy Burgess, whom he claimed to have first met at Cambridge in 1932.

Jackie Hewitt, who was successively the lover of Burgess then Anthony Blunt, two of the Cambridge spy ring, has described how he first met them. He was a nineteen-year-old working class boy from the north-east, who had run away to London and was appearing in the chorus line of the revue No, No Nanette at the London Hippodrome. He was picked up by a Hungarian in the Bunch of Grapes pub in Westminster and found himself at a party in a flat inside the War Office, the home of the resident clerk, Tom Wylie. The guests were about twenty gay men, all with upper-class accents, behaving as if they were appearing in a scene from a Noël Coward play. Burgess and Blunt were among them and it was Burgess who took the young man home to his flat in Chester Square, Belgravia that night.119 This was the milieu in which Putlitz mixed and he was a frequent visitor to the Chester Square apartment. Hewitt was persuaded by Burgess to sleep with Putlitz, describing it as ‘comfort for the troops’, and was under the impression that he was acting as a kind of Mata Hari, seducing the German diplomat for the benefit of Theodor Maly, Burgess and Blunt’s Russian intelligence handler.120 This was not necessarily so. As MI5 would discover many years later, Putlitz was probably working for the Russians even before he signed up for Vansittart’s private intelligence network.

Nevertheless, Peter Wright, the assistant director of MI5 who investigated the Cambridge spy ring in the 1960s and 1970s, regarded the information Klop extracted from Putlitz as priceless – ‘possibly the most important human-source intelligence Britain received in the pre-war period’.121

General Leo Geyr von Schweppenburg left his position as military attaché in mid-October 1937 to take over command of the 3rd Panzer Division in Berlin. During his four-year tenure in London he trod a difficult line between loyalty to his country and anxiety to avert the war that he knew was coming. His relations with some of the British military establishment were good, among them the director of military operations and intelligence Major General Sir John Dill, Colonel Bernard Paget, head of the Western European section at the War Office, and Sir Basil Liddell Hart, the anti-appeaser and military strategist. Geyr had formed a firm friendship with Klop, whom he regarded as an exceptional journalist and ‘a clever and most amusing person who had many good friends among the English’.122 The general’s father had been Master of Horse to King Karl of Württemberg whose wife Olga granted Klop’s father German citizenship.

One evening in 1938, shortly before Prime Minister Neville Chamberlain flew to Munich to try to reach a deal with Hitler over his demands to re-draw the Czech border, Peter Ustinov returned to the Redcliffe Gardens flat from drama school to find Klop in a state of mysterious agitation. There were glasses on the table, a bottle of champagne on ice, an open box of cigars. Guests were clearly expected imminently. Peter was ordered to make himself scarce and given ninepence for a cheap seat at the local cinema. He met the guests on the way out:

We lived on the fourth floor. As I went down the stairs there was a group of old men climbing the stairs laboriously. They were like a lot of elephants looking for somewhere to die. I stood flush against the wall as they passed.

The meeting had been arranged by Geyr von Schweppenberg who brought with him other members of the German high command who had flown to London incognito. He had apparently phoned from a callbox to arrange the meeting and told Klop:

We simply must get the British to stand firm at Munich. It is the last chance we have to stop Hitler. 123

It was to no avail. The British suspected a trap to goad them into a war they were still in no position to fight.

That, at least, was the explanation Klop gave to his son Peter some years later and the substance is confirmed by unpublished MI5 files.124 The exact date of the secret rendezvous is not clear but it appears to have been in the second half of August. It was not the only indication that the British government had during August that some senior figures in the German Army would contemplate overthrowing Hitler to prevent the forthcoming conflict. Apart from Klop’s rendezvous with the generals in his flat, there were at least two other secret military visits to Britain.

Geyr von Schweppenburg handed over a ‘strictly secret’ four-page directive circulated by Ribbentrop saying that the problem of Czechoslovakia must be solved by early autumn, by war if necessary. Hitler was confident Britain and France would not intervene. Detailed instructions for mobilisation were given and a date for action was stated as before 20 September.

However, Hitler’s army chief of staff, General Franz Halder, and his commander in chief, General Walther von Brauchitsch, believed that the projected invasion of Czechoslovakia would provoke a response from Britain, France and Russia that would lead to a world war that Germany could not win. They began drawing up plans for the army to arrest the Führer if he tried to declare war on France and Britain. In August 1938, Ewald von Kleist visited London as an emissary of the dissident army faction to urge Britain to stand firm against Hitler. He saw Vansittart and told him Hitler was determined on war and that although the generals were opposed to it they could not prevent it without outside help. He wanted a guarantee that France and Britain would intervene if Hitler ordered an attack on Czechoslovakia: that would be sufficient for the generals to act. Vansittart informed the Prime Minister and the Foreign Secretary. Chamberlain’s vacillating reaction was to say: ‘I don’t feel sure that we ought not to do something.’ Kleist then saw Churchill, who was more positive, saying that he felt certain France and Britain would respond to an armed attack by Germany on her neighbour but that once committed there would be terrible warfare that might take years to resolve. Within a fortnight the generals tried again. Colonel Hans Böhm-Tettelbach, acting on behalf of Halder and General Hans Oster, deputy head of the Abwehr, visited his old friend Julian Piggott who had been British Commissioner in Cologne after the First World War.125 Piggott was an occasional lunch guest of the director of MI5, Sir Vernon Kell, who sent a major from the intelligence service, probably Dick White, to hear what Böhm-Tettelbach had to say and passed it on to Vansittart.126 But the Prime Minister still doubted the resolve of the German officers to stage what would effectively be a military coup. Chamberlain also had to be careful not to be trapped into conspiring to overthrow the legitimate government of a country with which Britain still officially had good diplomatic relations. And, if the putsch failed, he would face leading a woefully unprepared country into war against an enemy whose military might and ambition was becoming ever more apparent.

The result was the opposite of what the German generals had hoped. On 15 September 1938, Neville Chamberlain boarded an aeroplane for the first time in his life and flew to Munich to try to reach some kind of compromise with Hitler over his demands for Czechoslovakia to cede the Sudetenland. On that very day, Geyr von Schweppenburg contacted Klop again and warned him that Hitler intended to bring about the dissolution of the Czech state by all or any means and that by 25 September mobilisation would have reached a stage whereby Hitler only needed to give the word and the invasion would start.127 In Munich, on 29 September, Britain, France and Germany agreed, without consulting the Czechs, that the Sudetenland should be ceded to Germany.

That postponed Hitler’s invasion plan, since he got what he initially demanded without the need for it. The consequence, as explained later by those dissident generals who survived the war, was to deprive them of their excuse for overthrowing him. There would be other occasions, before war was finally provoked a year later, when a putsch would have been justified but the moment had passed and the impetus was dissipated.

On 7 November 1938, MI5’s senior staff handed to the director Sir Vernon Kell a dossier running to around forty pages setting out the array of warnings they had received from four highly placed German moles about Hitler’s intentions. The bulk of it was Klop’s work, particularly from his contacts with Putlitz and Geyr von Schweppenburg. Kell took it to Vansittart and to his replacement as permanent under-secretary at the Foreign Office, Sir Alec Cadogan. He in turn showed it to the Foreign Secretary, Lord Halifax, upon whom it is said to have made a considerable impression and he showed it to the Prime Minister. In diplomatic language it made clear that MI5 did not understand the government’s emollient attitude to Hitler when so much of the evidence pointed to his aggressive attentions. Nothing that had happened in Czechoslovakia should have come as a surprise, they said. It was beyond doubt that there were forces in the German government, represented by Ribbentrop and Goebbels, that had not hesitated to risk war with Britain over Czechoslovakia. Hitler may have taken notice of the more cautious advice of his chiefs of staff on this occasion but, the report went on,

these aggressive elements are, and will continue to be, a very dangerous factor in the general situation. There is however reason to suppose that since the crisis Hitler, convinced of the weakness of England, is likely to adopt a different attitude in future.

They highlighted reports coming out of Germany that the government intended to put up to half a million people in concentration camps and authorise mass executions of political prisoners at Dachau.

Without naming him, the authors described Putlitz, making clear that he was working in what he believed was the best interests of his own country and accepted no payment for his information, which they described as scrupulously accurate. They made special mention of the dismay and exasperation Putlitz felt at the hopeless failure of the British government to recognise Hitler’s Machiavellian tendencies. He had told Klop that ‘the English think they are wise and strong. They are mistaken. They are stupid and weak.’

The report revealed that Geyr von Schweppenburg had also warned the government during the Munich crisis that if war had been declared the Luftwaffe’s first act would have been to concentrate all its resources on a bombing raid on London. The authors concluded:

Putlitz left London in May 1938 to take up the position of First Secretary in the German embassy at The Hague. MI5 still had excellent sources within the German embassy, presumably still using Klop as an intermediary. They were better informed about what was going on inside the German embassy at 9 Carlton House Terrace than they were about 10 Downing Street, with the result that they found themselves spying on their own Prime Minister.

On 23 November 1938 they trailed the embassy press officer Fritz Hesse, knowing that he had arranged a clandestine meeting, supposedly with someone from No 10. They observed a two-hour discussion with a man the watchers did not immediately recognise but who was soon identified as George Steward, the Prime Minister’s press secretary.

Within days MI5 was able to lay a copy of Hesse’s account of the meeting on the desk of Alec Cadogan. They even updated it with a revised version which had been sent to Ribbentrop after amendments by the ambassador Herbert von Dirksen. It showed that Steward had proposed an extraordinary agreement to limit the horrors of war, including a ban on poison gas and limitations on bombing civilians or a nation’s cultural treasures. Steward said it would paint Hitler in a more sympathetic light with the British public. Hesse reported:

This surprising suggestion is another sign of how great the wish for an understanding with us is here in England and is also evidence for the point of view that Great Britain is ready, during the next year, to accept practically everything from us and to fulfil our every wish.

The meeting took place only weeks after Chamberlain had returned from meeting Hitler in Munich, waving aloft the piece of paper representing ‘peace for our time’. But the deal, which followed Hitler’s occupation of part of Czechoslovakia, was already falling apart. Early in November, the Kristallnacht, during which Nazis ransacked synagogues and Jewish homes across Germany, had outraged British opinion.

Cadogan, generally perceived as far more appeasement-minded than Vansittart, agonised over what he should do. His private thoughts, only released in the National Archives in 2011, were that if he revealed to his own Foreign Secretary, Lord Halifax, that Chamberlain had gone behind his back to do secret deals with Hitler, Halifax might resign. If Halifax confronted Chamberlain, the PM

Britain would look weak and divided. Hitler might be tempted to stage an immediate military showdown before Britain had a chance to rearm and prepare to fight. On the other hand, Cadogan did not want to be accused later of suppressing vital intelligence. He described the appeasement faction as ‘Tiger-riders’ who were playing an appallingly dangerous game. He decided he must tell Halifax, who in turn confronted Chamberlain. The Prime Minister professed he was ‘aghast’ at the revelation and promised to put a stop to it, although the idea that Steward might have acted without Chamberlain’s authority seems preposterous. In reality, all that happened was that Steward was warned about ‘indiscreet talk’.

Dick White had befriended Hesse when he spent several months of 1936 in Germany, but Hesse was a loyal servant of Ribbentrop and continued to work for him throughout the Second World War. In 1946 he was flown to Britain to be interrogated by his predecessor, Klop, who revealed that MI5 had kept a record of his conversation with Steward. Hesse told him that he had been in secret contact with Steward from 1937 onwards and with Chamberlain’s special adviser Horace Wilson after Munich. He explained:

My relations with the Foreign Office were quite normal and they helped me in any way I asked them. The secret talks I had here were at the instigation of No. 10 and I was their instrument … My defence is that I was used from the other side. I was a journalist, half and half in disfavour with the Germans. Then there comes the secretary to the Prime Minister and asks me to help.130

The incident did not dissuade Chamberlain from pursuing his appeasement policy. Neither did the warning, three weeks later, from Sir Hugh Sinclair, director of MI6, that Hitler was bent on world domination and that:

From that point onwards warnings came thick and fast about Hitler’s aggressive intentions, not only in the east towards Czechoslovakia and Poland but in the West where war with Britain and France was also countenanced. Between December 1938 and April 1939 there were twenty secret reports, among them the dire threat that Hitler’s first aggressive act would be to bomb London, possibly as early as March 1939. Not all the reports were accurate and some may well have been planted by Admiral Canaris of the Abwehr, either to provoke Britain into a robust response or to test Chamberlain’s resolve. MI6 predicted that Hitler would find a quarrel to justify an invasion of Holland, initially wrong but ultimately true, and accurately forecast the annexation of the remainder of Czechoslovakia.132 And while the Prime Minister clung to the hope of peace he was not blind to the fact that Britain was unprepared for conflict if it came. Production of aircraft, particularly fighters, was stepped up, and a Military Training Act requiring all men aged twenty and twenty-one to spend six months under arms was passed in April 1939. An agreement was entered into with the French to defend Holland if Hitler attacked and talks began in Moscow to persuade Stalin to side with the Western Allies, effectively encircling Germany. Stalin, fearing that the Allies hoped to turn Hitler eastwards for an attack on Russia, chose instead to sign a peace treaty with the German dictator.

From the perspective of the German Army officers still trying to avert a war with Britain and France, none of these measures was likely to convince Hitler to back off. As late as July 1939 they despatched Lt Col. Gerhardt Count von Schwerin, the head of the British section of the German war ministry intelligence department, to warn of Hitler’s determination to attack Poland. Schwerin was a guest of the director of naval intelligence, Admiral John Godfrey, at a dinner party given by retired Admiral Sir Aubrey Smith at his home in Gloucester Place, Marylebone. Also present were James Stuart MP, parliamentary whip, representing the Prime Minister, and General Sir James Marshall-Cornwall, a former MI6 man who was now director general of air and coastal defence. He recalled that ‘a good deal of good champagne was consumed’.

Schwerin recommended that Churchill should replace Chamberlain as PM, a battle squadron should sail to the Baltic to make a show near Danzig and RAF bombers should be stationed in France. His hosts severely deflated these ambitions. James Stuart explained that replacing the PM would bring down the government; Godfrey said the Admiralty would never allow its capital ships to be at risk in the Baltic where they could be mined or torpedoed; and Marshall-Cornwall pointed out that French airfields had already been prepared to meet RAF bombers if needed. Schwerin’s proposals were duly passed to the Prime Minister who balked at anything so provocative.133 One Foreign Office official dismissed Schwerin’s arguments as ‘gross treasonable disloyalty’, while another pointed out that the German Army seemed to expect Britain to save them from the Nazi regime.134