After the first world war MI5 declined in importance. But with the growing fears of communism in the 1920s and 30s a new threat emerged - not just communist agents from abroad, but British communists who might betray their own country.In many cases they came from the same upper classes as those running the secret services. And a strange dance began - of toffs suspecting toffs.
"Bugger All!" is more like it.
Would anyone be surprised if the name Hoover shows up in further investigation?