Cryptanalysis of the Enigma bombes were, however, very fast and the most successful. They were extensively used by Bletchley Park over teleprinter links (using the Combined Cipher Machine) to OP-20-G for both 3-rotor and 4-rotor jobs. Although the German army, SS, police, and railway all used Enigma with similar procedures, it was the "Luftwaffe" (Air Force) that was the first and most fruitful source of Ultra intelligence during the war. The messages were decrypted in Hut 6 at Bletchley Park and turned into intelligence reports in Hut 3. The network code-named ‘Red’ at Bletchley Park was broken regularly and quickly from 22 May 1940
The World That Never Was as "intriguing, provocative and written with a novelist’s eye for detail ... an engrossing journey". In "The Guardian", anarchist writer Stuart Christie noted the relevance of the book's themes to contemporary tactics in policing and the Metropolitan Police Service's reluctance to make public files from the 1890s. Francis Wheen, writing in the "Financial Times", wrote that the book was "exhilarating" and questioned whether "the world that never was – one ignoring borders, and divisions of class and religion – [might] resemble the world as it might one day be"; while Peter Preston of "The Observer" described Butterworth's story as one