Secret Life of Bletchley Park - McKay Sinclair [98]
This in turn caused the administration at Bletchley Park great anxiety; for what if the Germans were to find Bertrand and his French cryptography experts and force them to reveal Enigma secrets? As it happened, by some extraordinary oversight, they never did. But there was an incident concerning General de Gaulle’s Free French forces. In 1943, General Henri Giraud announced to a crowd that he had seen an intercepted message from a senior ranking German. This in turn was reported in London in The Times. An incandescent Churchill demanded an immediate investigation at Bletchley Park. The administration could not find any message or decrypt that matched the one that General Giraud claimed to have seen. Once again, it was a claim that appeared to set off no alarm bells within German intelligence; nevertheless, Bletchley Park ensured that the Free French were never passed any identifiable decrypts.
Another dramatic naval battle in 1943 was to hammer home both the Park’s tremendous power and its peculiar vulnerability. In September of that year, Ultra decrypts were revealing, in close detail, the movements of the powerful German battleship Scharnhorst. This vast vessel, responsible for the sinkings of many Allied merchant ships, had become a near obsessive target for the British navy. It was based in Altenfjord, Norway. And by Christmas 1943, thanks to Enigma decrypts, enough was known of the ship’s movements and intentions for the navy to strike.
After an extraordinary chase through the black northern waters involving many warships – Sheffield, Norfolk, Belfast, Duke of York – while the Scharnhorst took repeated evasive action, changing course desperately, it was finally run down. Duke of York scored a palpable hit, and shortly, torpedoes from the other ships were searing through its hull. Thanks to the continuous stream of communications being decrypted at Bletchley – and instantly passed on to the Admiralty – the mighty Scharnhorst sank beneath the waves on 26 December 1943.
In the spring of the following year came a renewed Allied attack on the last of the great German marauders, Tirpitz, after other attempts had ended in failure. The ship was harboured, once again, at Altenfjord. Guided by Enigma decrypts concerning the time it intended to set sail, an Allied bomber raid was unleashed one dawn in March. While extensive damage was done – and a great many sailors were killed – it wasn’t quite enough. And this, it seemed, was also a very near miss for Bletchley.
‘It was as well,’ noted John Winton, ‘that the Germans remained absolutely confident that the Enigma was inviolate. Even the least suspicious … might just have wondered why, after Tirpitz had been so many months under repair, a powerful and clearly well-briefed and trained force of enemy aircraft should just happen to arrive overhead, not only on the day but at the hour, even at the very minute, when Tirpitz was putting out to sea.’11
Nevertheless, information from Enigma decrypts meant that Tirpitz was dogged as closely as if she had been bugged. Her final battle came a few months later, once more off the coast of Norway. This time she sank, taking over 1,000 of her sailors with her.
But the secret of Bletchley could so easily have been deduced by the Germans. Indeed, it still remains a matter of some wonder that it was not; manoeuvres and battles of this sort would always carry that inevitable risk. But the authorities at Bletchley – with thousands now working at the Park – faced an equally pressing and constant anxiety. Regardless of the Official Secrets Act, and the need for utter secrecy being impressed hard upon all those who