The Plot against PM Harold Wilson

There were threats of a coup d'état against the Wilson government, which were corroborated by leading figures of the time on both the left and the right. Wilson told two BBC journalists, Barrie Penrose and Roger Courtiour, who recorded the meetings on a cassette tape recorder, that he feared he was being undermined by MI5.

The first time was in the late 1960s after the Wilson Government devalued the pound sterling but the threat faded after Conservative leader Edward Heath won the election of 1970. However, after a coal miners' strike Heath decided to hold an election to renew his mandate to govern in February 1974 but lost narrowly to Wilson.

There was again talk of a military coup, with rumours of Lord Mountbatten as head of an interim administration after Wilson had been deposed.

In 1974 the army occupied Heathrow Airport on the grounds of training for possible IRA terrorist action at the airport. Although the military stated that this was a planned military exercise, Downing Street was not informed in advance, and Wilson himself interpreted it as a show of strength, or warning, being made by the army.