As this book makes clear, Churchill was very much aware of Ultra and its vital importance during the war and was kept fully abreast of its progress. He described the code breakers as 'the geese that laid the golden eggs and never cackled'. He paid a surprise visit to Bletchley in 1941. following which some senior members of the team, including Alan Turing, wrote a letter to Churchill and delivered it in person. In this they said that they were unable to get enough staff and this was holding up their work. Churchill responded immediately and forcefully, demanding 'action this day', and there was a dramatic and sustained increase in staff recruitment. By the beginning of 1945, in the preparation for D-Day, over 10,000 people were involved.
The need for secrecy is a recurrent theme in the book. It was vital to prevent the Germans from knowing that their ciphers were being cracked, and this was achieved completely . For this reason Churchill's speech to Parliament describing the massacres that the Germans were carrying out in Eastern Europe did not mention that this was a largely anti-Jewish crime. If this had been made known the Germans would have realised that their messages had been intercepted, but Churchill was criticised for omitting to mention the fact.
There was one startling failure in security: one of those working at Bletchley was a KGB spy and sent information to Russia about what was going on. This might have had disastrous consequences if the Germans had got wind of it.
A number of people who later became well known in other fields figure in these pages. They include Roy Jenkins, the novelists Angus Wilson and Ian Fleming, and the academic and writer F.L. Lucas, whose book Style I have previously reviewed. Lucas had an important role at Bletchley. Although he is not specifically credited for it here, it was he who spotted that Hitler was about to turn on his erstwhile ally Russia.
The importance of Ultra was not always recognised by those who were most likely to benefit from the information it provided, particularly in the early years. After the Italians had been routed in North Africa in 1941 Ultra detected that Luftwaffe escorts were attending convoys between Naples and Tripoli and concluded, correctly, that this meant that German troops were being sent to support the Italians. Their report was ignored by the Admiralty and the Air Ministry and was not forwarded to Cairo; a few days later British troops had their first contact with the Afrika Korps. But after the final defeat of Rommel, in considerable part due to information from Bletchley, attitudes changed considerably, although not completely.
Montgomery's reputation based on his success in North Africa owed a lot to information from Ultra. Yet the Allies' defeat at Arnhem was due to his ignoring warnings from Bletchley that there was a Panzer division in the area. And the Allies also failed to appreciate warnings, once again contributed by Lucas, that the Germans were about to launch a major counterattack in the Ardennes, even though two people from Bletchley flew to SHAEF headquarters in Paris to give the news.
It is unlikely that the war would have been lost without Ultra but it almost certainly would have lasted longer. Ultra contributed enormously to the overcoming of the U-boat attacks in the Atlantic and to the invasion of Europe, when it confirmed that the Germans had been completely taken in by the deception that pointed to the attack being launched at the Pas de Calais. If they had realised that Normandy was the target it is quite possible that the invasion would have failed.
The code breakers at Bletchley were a mixture of dons with a linguistic or classics background and much younger mathematicians. Some of the dons were notably eccentric but this was not seen as a problem. The book is strong on the personalities of those involved, with plenty of reminiscences and excerpts from diaries and other documents written at the time. The technical aspects of decipherment are covered pretty well but some of this, I felt, could have done with more detail. For example, we are told that the function of the 'Bombes', a kind of computer precursor (not to be confused with Colossus, which was in fact a computer) was enhanced by the addition of a 'diagonal board', but there is no explanation of how this worked.
One topic Smith covered that I had not much thought about previously but which was clearly vital was how the encrypted texts that the code breakers worked on were obtained. There were listening stations in Britain and, increasingly, abroad where German communications in Morse code were transcribed by mostly female operators. They had to wait, often for hours, until a message began to come through, and then write it down frantically by hand before forwarding it to Bletchley. This is just one of innumerable ways in which the work of the code breakers was only made possible by a huge army of co-workers.
Decrypting did not stop after the German surrender; it continued in order to provide information about the war with Japan. By this time US code breakers were also collaborating closely. A disturbing fact that emerged from this work is that the Japanese would have surrendered before the dropping of the atonic bombs if the Allies had assured them that the Emperor would not have to abdicate. "Given that they received this assurance in the subsequent peace deal, it is impossible to comprehend why the horrors of Hiroshima and Nagasaki were inflicted on the Japanese."
I find this appalling. Was it because the Americans wanted to see what the effects of an atomic bomb on a city would be—twice?
One good feature of the book is that it contains an clickable index; something I haven't found in a kindle version of a book previously. This is needed because there are so many people to keep track of that it is easy to forget who's who.