Operation Cold Water
Although as the previous chapter has indicated, some controversy still remains as to the exact time the British first learned of the Coventry raid, it now appears clear that by 1300 hours on the afternoon of November 14, they could have reasonably assumed that Operation Moonlight Sonata was scheduled to take place later that night. They had access to this information from their monitoring of German radio beam activities and from their previous receipt of enemy reconnaissance reports, as well as their reception of messages that had been sent from German Central Control to Versailles. By 1500 hours that same afternoon, British radio monitors were further able to detect that the X-Verfahren beams were intersecting over Coventry. From this information they could then reasonably conclude that Coventry was indeed the intended target for the Luftwaffe raiders for that night. It was now time for the RAF to put their previously developed counteroperation, Cold Water, into effect. British records indicate that this operation was begun at 1415 hours that afternoon.
On November 12, 1940, Wing Commander G.W.P. Grant of Air Intelligence sent a memorandum coded "Most Secret" to the Directorate of Home Operations alerting them that Air Intelligence had been able to piece together information that indicated the GAF was planning a major raid on the United Kingdom, and the raid was to be called Moonlight Sonata. The British had not, however, been able to determine an exact date for the operation, but from the codename it was assumed that the raid would be at night, during or near a full-moon period, and that the raid would most likely be conducted in threephases. From their interception of radio call signals the Germans transmitted on November 9 regarding this operation, Air Intelligence determined that bombers from both Luftflotten 2 and 3 would be used in the planned attack, as would also the elite pathfinder bombing group KGr 100. Air Intelligence (AI) had been able to put together this information from both their radio interception operations and their Ultra activities. It is important to note, however, that nowhere in this information was there any direct reference to Coventry as the proposed target of Moonlight Sonata.