deception operations against the Germans, aided by the capture of all of the German agents in the United Kingdom and the systematic decryption of German Enigma communications. Once Normandy had been chosen as the site of the invasion, it was decided to attempt to deceive the Germans into thinking it was a diversion and that the true invasion was to be elsewhere. At that stage of the war, Allied and German intelligence operations were heavily mismatched. Through the signals work at Bletchley Park, many of the German lines of communication were compromised since intercepts, codenamed Ultra, gave the Allies insights into how effectively their deceptions were operating. In Europe, the Allies had good intelligence from resistance movements and aerial reconnaissance. By comparison, most of the German spies sent into Britain had been caught or had handed themselves in and turned into double agents (under the XX System). Some of the compromised agents were so trusted that by 1944, German intelligence had stopped sending new infiltrators. Within the German command structure internal politics, suspicion and mismanagement meant intelligence gathering had only limited effectiveness. By 1943, Hitler was defending the entire western coast of Europe, with no clear knowledge of where an Allied invasion might land. His tactic was to defend the entire length and to rely on reinforcements to respond to any landings quickly. In France the Germans deployed two Army Groups. One of them, Army Group B, was deployed to protect the coastline; the Fifteenth Army covering the Pas-de-Calais region and the Seventh Army in Normandy. Following a decision to defer the invasion, Operation Overlord, until 1944, the Allies conducted a series of deceptions intended to threaten invasion in Norway and France. Bodyguard was preceded in late 1943 by Operation Cockade, which was intended to confuse the German high command as to Allied intentions and to draw them into air battles across the Channel. In that respect, Cockade was not a success, with German forces barely responding even as a fake invasion force crossed the channel and turned back some distance from its "target". Plan Jael Planning for Bodyguard began even before Operation Cockade was fully under way, following the decision that Normandy would be the site of the coming invasion. The departments responsible for deception, 'A' Force, COSSAC's Ops (B) and the London Controlling Section, began to address the problem of achieving tactical surprise for Overlord. They produced a