‘It is high time for me to put an end to your sitting in this place,’ declared Oliver Cromwell to the Rump Parliament in April 1653. ‘Ye are a factious crew, and enemies to all good government … In the name of God, go!’

Leo Amery, a Conservative backbencher, brought Cromwell’s final six words into the House of Commons on 7 May 1940. He was unsure whether he would use them in the debate over Norway, where British and French forces were withdrawing from the first major land confrontation of the war. Colonial Secretary in the Conservative governments of the 1920s, Amery was a passionate advocate for the British Empire and strongly anti-communist. In the 1930s he became a tough critic of his own party’s appeasement of Nazi Germany. Speaking late in the debate, Amery felt the House was with him, and he ended his speech as Cromwell had done. Neville Chamberlain survived the division, but not the collapse in support from a fifth of his backbench, galvanised by Amery and others.