Electoral system for national legislature

UK Parliament, Background to Voting systems in the UK, accessed 10 December 2019

"First past the post is the current system for electing MPs to the House of Commons. The UK is divided into 650 separate constituencies, each of which elects a single Member of Parliament. Winning candidates must receive more votes than any other candidate; they do not need a majority of all votes cast in order to be elected. First past the post is also used for local elections in England and Wales."