I read this novel in the early 1990s. It was set in a contemporary British town. The (male) viewpoint character was a school student, who befriended a student (also male -- name might have been "Andy", but not sure) who had just transferred to his school. 

This transfer student had the psychic ability to summon up events in the town from the Second World War. I don't remember if he and the viewpoint character could just see images, or if he could actually take them back to those events and they could influence them. (And this may not have been clear to the viewpoint character himself.) The psychic ability may only have manifested in certain places where important events (deaths?) had taken place.

After some adventure involving this ability (possibly connected with an air-raid during the war?), the viewpoint character finds that his friend hasn't come to school.

The teacher informs him that his friend transferred away, and there was no information about where he had gone because his father had some sensitive government job. (This ending is absolutely clear in my memory.)