Light The Blue Paper - S3.E4

The bang is loud in the night. The conspiracy of silence which follows is more sinister. When an explosion destroys Bill Webster's betting shop CID runs up against a blank wall. No clues and there is nobody willing to talk. Webster himself stubbornly maintains it was an accident, but Barlow is convinced there is a connection between the explosion and the fact that Webster intends to compete with his rivals by opening more shops in the area.