Newsnight's Julian O'Halloran investigated the shadowy world of espionage with the revelation that then then-Prime Minister Harold Wilson and other members of his government were possibly bugged and burgled in the 1970s.

Those behind the allegations claimed that an intelligence services' "dirty tricks" campaign attempted to undermine Wilson's Labour government.

Newsnight's librarian Adam Gotch chose this classic Newsnight investigation because it used lots of the BBC's rich archive to help tell the story, and because it helped clarify the situation about whether or not the rumours of Harold Wilson being bugged were true - by going straight to the people who knew.

Originally broadcast on 5 December 1986.

A special programme to mark Newsnight's 30th anniversary will be broadcast on Saturday 23 January 2010 at 8pm on BBC Two.