The purging of Members of Parliament hostile to the politicised New Model Army, carried out on 6 December 1648.
The purging of Parliament was first proposed after the ending of the First Civil War in the manifesto known as the Declaration of the Army. It was issued in June 1647 when Presbyterian MPs were attempting to disband the New Model Army without settlement of the soldiers' grievances. The Army occupied London in August, after which Agitators again demanded a purge, resulting in the departure from London of several of the Eleven Members, who were regarded as the Army's leading opponents in Parliament. Lieutenant-General Cromwell supported the Agitators at this time but a full purge was prevented by the opposition of General Fairfax. On 20 August 1647, Cromwell stationed a cavalry regiment at Hyde Park and marched under armed escort to take his seat in the House of Commons. This display of force coerced many Presbyterians into withdrawing from Parliament, leaving the House of Commons for a time with an Independent majority whose views were broadly in line with those of the Army.
In November 1647, Lieutenant-Colonel Jubbes proposed the purging of Parliament at the Putney Debates. By then the attention of the Army radicals had shifted to the removal of MPs opposed to bringing the King to account. Their attitude was further hardened by the King's alliance with the Scots, resulting in the Second Civil War, and by his refusal to compromise in negotiations even when the Royalists had been defeated a second time. Despairing at the King's obstructiveness during negotiations for the Treaty of Newport, Commissary-General Ireton wrote to Fairfax advocating the purging of those Members of Parliament who continued to work for a negotiated settlement, but Fairfax rejected the idea. Meanwhile, Presbyterian MPs were determined to seek further negotiations with the King.
By December 1648, Ireton, with the support of Colonel Harrison and other radicals, was proposing the enforced dissolution of Parliament. This was opposed by John Lilburne and the Levellers. Independents who supported the Army argued that dissolution would be a slower and less efficient way of dealing with their immediate political problems. At a meeting at Whitehall on 5 December between Army officers led by Ireton and Independent MPs, it was decided to use military force to purge Parliament rather than dissolve it.
Early in the morning of 6 December 1648, troops commanded by Colonel Thomas Pride occupied the approaches to the House of Commons. Pride himself was stationed on the steps leading to the entrance of the House with a list of 143 MPs regarded as antagonistic to the Army. His orders were to prevent the proscribed Members from entering the House. Any who resisted were to be arrested. Pride was seconded by Sir Hardress Waller and accompanied by Lord Grey, who identified the proscribed MPs as they approached. Most turned back or stayed away, but 45 who refused to go were arrested and placed in confinement. The imprisoned Members were held overnight in a nearby tavern familiarly known as "Hell". They were all released within a few days after giving an undertaking to make no attempt to return to their places in the House of Commons.
The Purge was carried out on the orders of Ireton. General Fairfax apparently had no knowledge of it, even though all the Army's actions were carried out under his name. He was said to be furious when he heard what had happened but did nothing to interfere. Cromwell arrived back in London from the siege of Pontefract the day after the Purge and announced his approval of the proceedings. By removing the MPs who still favoured a negotiated settlement, the Purge effectively cleared the way for the King's trial the following month.
50 Independent MPs and 30 others (many of whom resigned in protest) were allowed to retain their seats. The purged House of Commons came to be known as the Rump Parliament.