BBC2, Friday, May 9, 9-10pm

The clandestine careers of Anthony Blunt, Kim Philby, Guy Burgess and Donald Maclean have a continuing fascination, though it is half a century since they were active as Soviet spies and the faith to which they dedicated their lives has crumbled. One reason is that the group came from the most privileged section of British society, making them on the surface unlikely traitors to that society. You need only dig deeper to see why they might be disaffected, despite their background and public school education.

Peter Moffat’s play concentrates on when the four met at Cambridge. He has invented or altered some episodes and characters, but the essential is here. Their inner struggles are part of the history of the 1930s.

Robin Buss