Britain is divided into 650 areas called constituencies. During an election everyone eligible to cast a vote in a constituency selects one candidate to be their MP. The candidate who gets the most votes becomes the MP for that area until the next election.
At a general election, all constituencies become vacant and a Member of Parliament is elected for each from a list of candidates standing for election. General elections happen every five years.
If an MP dies or retires, a by-election is held in that constituency to find a new MP for that area.
Most MPs are members of one of the three main political parties in the UK – Labour, Conservative and Liberal Democrat. Other MPs represent smaller parties or are independent of a political party.
To become an MP representing a main political party a candidate must be authorised to do so by the party’s nominating officer. They must then win the most votes in the constituency.
The UK Parliament has MPs from areas across England, Scotland, Wales and Northern Ireland. In addition, there is a Parliament in Scotland, a National Assembly in Wales and a National Assembly in Northern Ireland.
Separate elections are held for these devolved political bodies (which have been granted powers on a regional level that the UK Parliament was formally responsible for) – candidates who win seats in these elections do not become MPs in the UK Parliament.