A general election can be called by the prime minister at a time of his or her choosing, up until 17 December 2024.

The prime minister must request permission from the monarch to hold a general election. With permission granted, a date will be set for the dissolution of parliament. Polling day takes place 25 working days after this date. This process is laid out under the Dissolution and Calling of Parliament Act 2022, which replaced the Fixed-term Parliaments Act 2011.

What happens in parliament once the election is called? 

There are normally several days between an election being called and parliament being dissolved. During this period, parliament will continue until it is either dissolved or prorogued (and then dissolved) – whichever comes first. This period is known as ‘wash-up’.

Any parliamentary business not completed by the end of ‘wash-up’ will fall. This means any bills that have not already received Royal Assent will not enter into law and cannot be continued into the next parliament. This leads to a rush to rapidly pass legislation through parliament to get it onto the statute book, normally requiring cooperation between parties to agree which bills they will support through this expedited legislative process.

The length of ‘wash-up’ is decided by the prime minister and can vary. Since 1992, the longest wash-up period was in 2017, when parliament sat for a further seven days after the election was called.

What happens once parliament is dissolved?

Dissolving parliament is a royal prerogative, exercised on the advice of the prime minister. At this point, all business in the House comes to an end and every seat in the House of Commons becomes vacant, meaning there are no longer any MPs. Government ministers, however, remain in post until a new government is formed after the election. Members of the House of Lords retain their positions but all business in the House ends.

Polling day takes place 25 working days after parliament is dissolved. ¹³ DaCoP 2022  Weekends, Christmas Eve and bank holidays (anywhere in the UK) do not count as working days. Polling day has been on a Thursday since 1935, but this – unlike for Scottish Parliament elections ¹⁴ Scotland Act 1998, S2 - has no basis in law and the prime minister could hold the election on any day of his or her choosing.

What happens in government once the election is called?

Government activity is restricted during the campaign, in what is known as the ‘pre-election period’ (previously known as purdah). This is to ensure public money is not used to support the campaign of the party in power, and to maintain the impartiality of the civil service. Often, these restrictions come into force once parliament has been dissolved, but the pre-election period can begin before this (as in 2017).