UK Parliamentary by-elections

Parliamentary by-elections in the United Kingdom occur following a vacancy arising in the House of Commons. They are often seen as a test of the rival political parties' fortunes between general elections.

Members of the House of Commons are not technically permitted to resign. Thus, members wishing to resign or seek re-election are appointed on their own request to an "office of profit under the Crown", either the Steward of the Chiltern Hundreds or the Steward of the Manor of Northstead. Appointment to such an office automatically vacates the Member's seat. A member who resigns in this manner may stand for re-election without resigning from the office of profit.

An election to the House of Commons is formally begun by the issue of a writ from the Clerk of the Crown in Chancery. In the case of a by-election, the Speaker must first issue a warrant to the Clerk of the Crown to allow the Clerk to issue a writ. The most common reason for the Speaker to issue a warrant is that he has been required to by a resolution of the House of Commons itself. This requires an MP to move a motion to command the Speaker to issue his warrant. Such motions are moved at the start of proceedings in the House of Commons.

Usual Parliamentary convention, codified by the Speaker's Conference in 1973, is that such a motion is moved by the Chief Whip of the party to which the former MP belonged. However, this convention is not always followed and such a motion is valid if correctly moved by any MP. This can arise because the former MP did not belong to a party: the writ for the by-election arising from the death of Independent Republican Frank Maguire was moved by Jim Molyneaux, leader of the Ulster Unionist Party, and after Bobby Sands died on hunger strike the writ for a second by-election was moved by Dafydd Elis-Thomas of Plaid Cymru. When all Unionist MPs from Northern Ireland resigned to force by-elections on the Anglo-Irish Agreement, the writs were moved by senior Conservative backbencher Sir Peter Emery.

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