House of Commons of the United Kingdom canister of chlorobenzylidene malonitrile (tear gas). Even members have been known to disturb proceedings of the House. For instance, in 1976, Conservative MP Michael Heseltine seized and brandished the Mace of the House during a heated debate. However, perhaps the most famous disruption of the House of Commons was caused by Charles I, who entered the Commons Chamber in 1642 with an armed force to arrest five members for high treason. This action was deemed a breach of the privilege of the House, and has given rise to the tradition that the monarch does not set foot in the House
House of Commons of the United Kingdom (see qualifications below), his or her seat falls vacant. It is also possible for the House of Commons to expel a member, but this power is exercised only in cases of serious misconduct or criminal activity. In each case, the vacancy is filled by a by-election in the constituency, with the same electoral system as in general elections. The term "Member of Parliament" is normally used only to refer to members of the House of Commons, even though the House of Lords is also a part of Parliament. Members of the House of Commons may use the post-nominal letters "MP".