The story of the code breakers at Bletchley Park has been told many times, so it needs a new approach to make another book on the same topic interesting. In this case that approach is to focus on how the intelligence generated by the code breakers was actually used, rather than on the code breaking itself.
One key strength of this approach is that the author looks at the failures to use the intercepted intelligence as well as the successes. This differs from many books on Bletchley, which will look at failures to actually get the intelligence, normally caused by changes in the German codes (extra rotors on the Enigma machines etc). Here we look at times where Bletchley was able to decode messages successfully, but that intelligence wasn’t used, or wasn’t used well. The most famous example of a negative result from the use of Ultra intelligence doesn’t actually fit into either of those camps – when Rommel first arrived in Africa intercepted messages made it clear that he had been ordered to stay on the defensive in western Libya, so when he ignored his orders and attacked anyway the Allies were caught out. However there are examples of a failure to use more accurate intelligence, such as the failure to realise the Germans were about to invade Norway in 1940.
The successes are of course more significant. We follow the use of Ultra intelligence in the war at sea, from Cape Matapan to the battle of the Atlantic, as it predicted German moves in North Africa, and in the build-up to D-Day (including the interception of Rommel’s initial report on the Atlantic Wall defences). Events on the battlefield are matched up to developments at Bletchley, as the process became ever more industrialised and the size of the operation continued to expand.
Overall this is a good attempt to find a new approach to the story of Bletchley Park, with more on the general military situation and the impact of Ultra than is normal, while still having plenty on the actual code breaking.
1 - Unlocking Enigma
2 - Bletchley Beats the Italian Navy
3 - Home Front to North Africa
4 - Atlantic War
5 - Bletchley 2.0
6 - Enigma Endgame
Appendix: Bletchley Today
Author: Michael Kerrigan