During the summer and autumn of 1939, German emissaries visited Dublin, proving their identities by matching a pound note that had been torn in half with one carried by their contacts. In August, the Abwehr, Germany’s overseas secret service, actually informed the IRA that war was coming – ‘probably in one week’. Meanwhile, MI6 had learned, at least in outline, of further meetings between the IRA and the head of the Abwehr, Admiral Canaris. At this point de Valera denied that there was any connection between the IRA and Nazi Germany, but MI6 knew otherwise.14
British intelligence overestimated the ‘backdoor’ threat because of an IRA bombing campaign on the mainland. The IRA was a small and divided organisation in the late 1930s and early 1940s, with innumerable splits between those who wanted to do little, those who wanted a guerrilla war against Ulster, and those who wished to bomb the British mainland. In 1939, the faction that advocated bomb attacks on England triumphed. Their plans were somewhat eccentric, and included blocking London’s sewers with two tons of quick-drying cement. Many of their explosives were homemade and most of their attacks failed. Even so, in June 1939 there were seventy-two IRA attacks in England. The worst came two months later, when a bomb exploded in a busy shopping street in Coventry, killing five people and injuring a further fifty-one. In early 1940, two IRA operatives, James McCormick and Peter Barnes, were hanged for their role in the bombing, after much debate in cabinet over their possible reprieve. In another incident, five hundred pounds of explosives were discovered in a raid on a chip shop in Manchester. De Valera refused intelligence cooperation against the bombers.15
There were a further fifty IRA attacks in the period up to May 1940. Churchill was particularly exercised, which formed the personal background to the panic about a German fifth column as he arrived in office. It clearly loomed large in the new prime minister’s imagination, and he sought the views of the chief of MI6 on German activity on the west coast of Ireland, asking, ‘Are there any signs of succouring U-boats in Irish creeks or inlets?’ He urged that more be spent on building up a better force of agents in Dublin. Sidney Cotton, an eccentric businessman who cooperated with MI6 and who pioneered aerial reconnaissance, was despatched on a survey of the west coast of Ireland in search of U-boats.16
Churchill arrived in Downing Street on 10 May 1940. Five days earlier, Hermann Görtz of the Abwehr landed by parachute in County Meath. A hardened spy who had been jailed for four years for his espionage activities in Britain in the 1930s, Görtz’s task was to establish a more permanent liaison with the IRA and develop detailed plans for attacks on Northern Ireland.17 The Garda raided one of his safe houses a few weeks later and recovered Görtz’s uniform, his parachute, documents referring to ‘Plan Kathleen’, and £20,000 in cash. The Dublin government brought some of those arrested before the courts, and the affair received considerable publicity.18 Görtz managed to evade the authorities for another eighteen months, and after his capture he committed suicide by biting on a glass phial filled with prussic acid.19 Guy Liddell, a senior MI5 officer, eventually came to regard the Görtz case as ‘fairly conclusive proof’ that the Germans were working in close conjunction with the IRA.20
In reality, the IRA was small and ineffective in May 1940. It admired Hitler no more than it had admired Stalin in the previous decade. These were merely opportunistic explorations on its part.21 But its expansive bombing campaign in England, together with some genuine instances of Nazi agents with secret radios and subventions of cash, gave substance to the largely fictional fifth-column menace. Hermann Görtz and his associates transferred some £50,000 to the IRA in this period. This was more than enough to alarm Downing Street. In May 1940, the nascent JIC warned that the IRA could rapidly grow to 30,000 members, and that German aircraft parts and spares had already been smuggled into Ireland. Churchill ordered plans for an invasion of southern Ireland to be drawn up using newly arrived Canadian troops.22
By the summer of 1940, the fifth-column menace appeared terrifying. The Netherlands and France had surrendered after only limited resistance. For Churchill, and indeed President Roosevelt, the most plausible explanation for this surprising turn of events was an insidious ‘enemy within’. In reality, Hitler’s thrust into Holland, Belgium and France was informed by excellent signals intelligence derived from the intercepted messages of the French high command, which also revealed British plans.23 Nevertheless, in July 1940, with Churchill’s approval, Roosevelt sent William J. Donovan, chief of America’s embryonic intelligence service, to Britain to investigate ‘fifth column methods’. He found a receptive audience. Churchill was now obsessed with the idea that a large fifth column was preparing the ground for a German invasion of Britain.
Donovan found hard facts difficult to come by. The British public were infected with what Churchill himself called a ‘spy mania’ – just as they had been in the First World War. German spies were seemingly everywhere. In one odd case, locals assumed a cattle stampede on the island of Eilean Shona off western Scotland was the work of German agents.24 The police, the army and the security services were inundated with reports about mysterious foreign men on trains, flashing lights assumed to be signals to the enemy, and above all the menace of carrier pigeons, which were seen as the main means for spies sending secret messages to Germany. An army of British birds of prey was marshalled to bring down the pro-German pigeons on their way back to the Fatherland.25 MI5 took the pigeon threat seriously, and even had its own anti-pigeon section under Flight Lieutenant Richard Melville Walker.26
The idea of a fifth column captured the popular imagination. One woman, a rare voice of scepticism, recorded the everyday experience: ‘From every part of the country there came the story of the Sister of Mercy with hobnailed boots and tattooed wrists whom somebody’s brother’s sister-in-law had seen in the train.’ Every unusual occurrence was explained by the hidden hand of Nazi agents. Remarkably, the newly formed Ministry of Information dismissed any doubts as further evidence of subterranean activity. Anyone who thought it could not happen in Britain, it insisted, had ‘simply fallen into the trap laid by the fifth column itself’, adding that the top priority of the fifth column was of course ‘to make people think that it does not exist’. In a perfect climate of conspiracy, doubters were themselves part of the vast plot. The police and security agencies were flooded by absurd reports of suspicious Nazi doings.27
Churchill had personal reasons for fearing subversion. Pro-German sentiment, often converging with virulent anti-Bolshevism, was rife amongst the British aristocracy. Lord Londonderry, Churchill’s own cousin and the government minister responsible for the RAF in the early 1930s, was notoriously pro-German. Although not a fascist himself, he sought to pursue friendship with the Nazis at any cost, flying to Germany to meet Hitler and Goering, and repeatedly hosting Ribbentrop and ‘a noisy gang of SS men’ in his stately home during 1936.28
Evidence of real Nazi spies in important places confronted Churchill within days of his arrival in Downing Street. On 18 May 1940, the Tyler Kent espionage case exploded, shaping the new prime minister’s immediate views on subversion and increasing his fears. Tyler Kent was a lowly cipher clerk at the American embassy in London, but he had close links with the Right Club, a pro-German and anti-Semitic group. He used an intermediary to pass top-secret documents, including summaries of conversations between Churchill and Roosevelt, to the Germans and the Italians. MI5 raided his flat and found 1,929 official documents, as well as Churchill’s cables and a notebook containing the names of people under surveillance by Special Branch and MI5. The haul also included agreements on Anglo–American intelligence cooperation. Kent’s espionage only