Timetable for by-election explained

Jamie Reed will step down as MP for Copeland when he takes up his new position at Sellafield on February 1st 2017. Mr Reed is taking on the role of Head of Development and Community Relations, where he will report directly to Chief Executive Paul Foster.

But when can we expect a by-election? Below is the timetable of events when an MP resigns.

Reasons for by-elections:

A seat becomes vacant during the lifetime of a Parliament either when an MP resigns from Parliament, for example to take up a job which by law cannot be done by an MP, or because an MP has died. The law also allows a seat to be declared vacant because of a Member's bankruptcy, mental illness or conviction for a serious criminal offence.

A by-election does not automatically take place if an MP changes political party.

Until a new MP is elected, constituency matters are handled by an MP of the same party in a neighbouring constituency.

'Moving the Writ'

Traditionally the Chief Whip of the political party whose MP held the vacant seat will begin the procedure for a by-election. This is known as 'moving the Writ' and takes the form of a motion in the House of Commons.

By-election timetable

A new Writ is moved within three months of the vacancy occurring. There have been a few instances of seats remaining vacant longer than six months before a by-election was called. Seats have also been left vacant towards the end of a Parliament to be filled at the general election.

If there are several vacant seats then a number of by-elections can take place on the same day.