Comment by minimax

Note for visitors to London from abroad: It's super easy to get to Bletchley Park from London. I think it took me something like 90 minutes total to get from my hotel in central London to Bletchley park on the train. The staff is well informed and very helpful. They have working replicas of the bombe and colossus machines. It's all very cool. Highly recommended if you have half a day to kill in London.