On the night of November 14, 1940, German bombers dropped 500 tons of explosives, 33,000 incendiary bombs and dozens of parachute mines on Coventry. A new play at the Belgrade Theatre in Coventry, One Night In November, claims that Winston Churchill knew of the attack several days in advance but held back the information [Let It Happen On Purpose - LIHOP ] to protect the most important secret of the war: the breaking of the German Enigma code at Bletchley Park. Churchill's biographer, Sir Martin Gilbert, reveals his truth about the events of that day:
On November 12, 1940, Enigma decrypts made it clear that a major German bombing raid was imminent. Its code name, Moonlight Sonata, had been read in the decrypts. The Air Intelligence report Churchill received on November 12 gave, on the basis of the latest intelligence, the following possible targets: central London, Greater London, the Thames Valley, Kent or the Essex Coast. A German pilot who had been shot down on November 9 had, under interrogation, suggested that Coventry and Birmingham would both be attacked in a “colossal raid” between November 15 and 20; but the senior Air Intelligence Liaison officer at Bletchley noted that there was “pretty definite information that the attack is to be against London and the Home Counties”.
Bletchley considered the German pilot's information “doubtful”. Churchill was sent a summary of these reports on the morning of November 14; he read them just after midday. Whatever the target, he was told, the usual counter-measures had been prepared since early that morning, and would be activated as soon as the precise target was known. The target area would be “probably in the vicinity of London”, Churchill read. If, however, “further information were to indicate Coventry, Birmingham or elsewhere”, it was hoped that the standard “Cold Water” instructions for counter-measures could be got out in time.
That afternoon, Churchill prepared to leave Downing Street by car to spend the weekend at Ditchley Park, one of his weekend retreats. As his car prepared to leave, John Martin, his Principal Private Secretary, handed him a top-secret message in a locked box. As the car reached the Albert Memorial, Churchill read the message. It was the latest intelligence: a heavy raid on London. He immediately told his driver to return to Downing Street, explaining to Martin that he was not going to spend the night peacefully in the country while the capital was “under heavy attack”. Early that evening Churchill waited at Downing Street for the expected attack on London, sending his two duty private secretaries, John Colville and John Peck, to the underground shelter at the disused Down Street station on the Piccadilly Line, telling them: “You are too young to die.” He also gave instructions for the “Garden Room Girls” - the typists - to be sent home. Churchill went on to the Air Ministry roof to await the bombing.
The moment German radio beams identified Coventry as the target, the Air Ministry ordered British planes to bomb the aerodromes from which the attackers were expected to take off. A continuous fighter patrol had been maintained over Coventry itself, and the “Cold Water” defence preparations were activated. As a result of an earlier raid on Coventry, Churchill had given instructions on November 7 to strengthen Coventry's anti-aircraft defences. These instructions had been carried out.
On November 12, Enigma had revealed a raid in prospect, but not the target. At the last moment on November 14, the beams revealed the target, and were acted on without delay.