There are several ways by which a Member’s seat may be vacated during the lifetime of a Parliament:

A Member wishing to resign their seat will be appointed to one of two offices of the Crown – Crown Steward and Bailiff of the Chiltern Hundreds or Crown Steward and Bailiff of the Manor of Northstead.

A Member may die.

A Member may be subject to a successful recall petition under the terms of the Recall of MPs Act 2015.

A Member may be expelled by resolution of the House.

A Member may be disqualified by becoming a Member of the House of Lords.

A Member may be disqualified by becoming a Police and Crime Commissioner, or a Member of the National Assembly for Wales, the Northern Ireland Assembly, or a non-Commonwealth legislature (except the Houses of the Oireachtas of the Republic of Ireland).

A Member may be disqualified by being sentenced to be imprisoned or detained indefinitely for more than a year in the United Kingdom, Isle of Man, the Channel Islands, or the Republic of Ireland; or if they are convicted of treason.

A Member may be disqualified, either by the voiding of the Member’s election

A Member may under certain circumstances be disqualified for bankruptcy.

A Member may accept one of a number of offices which are incompatible with membership of the House of Commons.

A Member who wishes to resign their seat must be appointed to one of two offices of the Crown, retained from antiquity for this purpose only. These are the Crown Steward and Bailiff of the Chiltern Hundreds and the Crown Steward and Bailiff of the Manor of Northstead. Other such offices have been used for this purpose in the past, and some of them have carried duties and salaries: this is not the case today. This process is often described as “taking the Chiltern Hundreds”.

In the past, Ministers were required to re-contest their seats following their appointment as ministers. This was in recognition of the possibility that being a Minister of the Crown – i.e. holding an office provided by the monarch – might constitute a conflict of interest with the duties of a Member of Parliament. This practice has now been discontinued.

Members who are recalled can contest the subsequent by-election. A Member who has taken an incompatible office can also stand if they resign the office. A Member whose election is voided may be permitted to stand, depending on how the election was voided.

This briefing paper details the purposes of the Chiltern Hundreds, the case of Gerry Adams, and debate about possible reforms. It discusses the historical background of Members resigning their seats and of Offices of profit under the Crown. It also summarises the other ways in which Members’ seats can be vacated.