British elections

General elections take place at least every five years on a First-past-the-post election system. But the actual date is chosen at the discretion of the current Prime Minister and elections are often held before the end of the five-year term. The five years runs from the first meeting of Parliament following the election.

The Prime Minister asks the Queen to dissolve Parliament by Royal Proclamation. The Proclamation the formal Writs of Election which require an election to be held. The election is held 17 working days after the date of the Proclamation.

Since 1935 every general election has been held on a Thursday. Of the 16 general elections between 1945 and 2001, four have been in October, four in June, three in May and two in February.

When all of the results are known, the Queen will usually invite the leader of the party winning the most seats in the House of Commons to be Prime Minister and to form a new Government. The second largest party becomes the Official Opposition. Any smaller parties are collectively known as the Opposition, even if they support the Government.

From the Electoral register (2000) there are 44,423,440 people registered to vote in the UK, 36,994,211 of them in England.

• A list of the Prime Ministers