Before the outbreak of war, deep pessimism prevailed among British cryptologists about the prospects of breaking the military Enigma. In view of the slim chances of breaking the cipher, there was no point in building a structure for distributing information from broken enemy messages. When an unexpected gift from Poland changed the mood, the missing signals intelligence structures had to be built from scratch. There was not enough time for this during the short campaigns in Norway and France, so the breaking of Enigma messages did not have a significant impact on them. The war in North Africa was to be the first stage in a conflict that lasted long enough for all the parties to treat it as a training ground for modern war. The special nature of the conflict in Africa also opened wide perspectives for codebreakers, who for the first time were able to provide substantial support for the troops fighting in the desert, as well as for sailors and airmen supporting and supplying them. During the African campaign the British learned not only to break the enemy’s ciphers, but above all to use the information gained in this way effectively. Learning has not been easy and painless; part of it were spectacular disasters suffered despite having precise information about the opponent’s intentions, coming from his broken ciphers. But at the end of the Mediterranean interlude, the whole of Allied signals intelligence represented a mature system, ready to play a decisive role in operations leading to victory.