In April 1944 Maurice Fogel made a throwaway comment during one of his shows: “I want you to keep in mind the fifth of June. That date will have special significance for you.” This was a regular moment in his performances: If something subsequently happened on the mentioned date he would take credit for the prediction, and if it didn’t he knew the remark would be forgotten. On this occasion, however, things took a turn for the worse when he was interrogated first by the military police and then MI5 as to what he knew about the fifth of June. Of course he knew nothing, having chosen the date at random, and the questioning was eventually dropped.
Why did this offhand comment draw the attention of government agencies? Well, at the time, preparations were being made for the fifth of June, which was the original date on which D-Day, the largest ever seaborne invasion, was planned. Of course those plans were top secret, and the fact that a mindreader seemed to refer to them in his show caused huge concern.