Columbia subject headings:
Great Britain--Politics and government--1945-
Great Britain. MI5.
Great Britain. MI6.
Intelligence service--Great Britain.
Political persecution--Great Britain.
Secret service--Great Britain.
Harvard subject headings:
Espionage, British.
Great Britain--Politics and government--1945-
Official secrets--Great Britain.
Princeton subject headings:
Great Britain--Politics and government--1945-
Great Britain. MI5
Great Britain. MI6
Intelligence service--Great Britain.
Political persecution--Great Britain.
Secret service--Great Britain.