Cryptanalysis of the Enigma immense problem and it gave a great deal of trouble. Work on a high speed machine had been started by Wynn-Williams of the TRE late in 1941 and some nine months later Harold Keen of BTM started work independently. Early in 1942, Bletchley Park were a long way from possessing a high speed machine of any sort. Eventually, after a long period of being unable to decipher U-boat messages, a source of cribs was found. This was the Kurzsignale (short signals), a code which the German navy used to minimize the duration of transmissions, thereby reducing the risk of being
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