Pro-European Tories like Michael Heseltine and Sir Edward Heath are not fighting for party position and will therefore not be cowed.

ECONOMIST: Roll up that map of Europe

Lord Saville of Newdigate has already heard evidence from more than 800 witnesses, including the prime minister in 1972, Sir Edward Heath.

BBC: Sir Mike was a captain in the Parachute Regiment at the time

After the last death of a former prime minister, Sir Edward Heath in 2005, the Commons staged an hour-long debate to pay tribute.

BBC: Manchester