Why the next general election must be called within the next 12 months

The countdown to the next general election has reached a symbolic moment, with exactly a year to go until the current session of Parliament must end.

December 17 2024 is the latest possible date by law for proceedings in Westminster to finish, ahead of the country going to the polls.

If a general election has not already been called by this date, Parliament will be dissolved automatically and an election must take place within 25 working days.

Christmas Eve, Christmas Day, Boxing Day, New Year’s Day and the Scottish Bank Holiday on January 2 are not counted when calculating the 25 days.

This means the latest possible date for the next general election is Tuesday January 28 2025 – although because the convention in the UK is for elections to take place on a Thursday, polling day would likely be January 23 2025.

The dissolution date is fixed as December 17 2024 because this is five years since Parliament first met following the most recent general election in 2019.

However, the Government can choose to call an election before this date.

To do this, Prime Minister Rishi Sunak needs to ask permission from the King to dissolve Parliament ahead of schedule.

Details of when the next general election must take place are set out in the Dissolution & Calling of Parliament Act 2022.

If Mr Sunak chooses to stick with the timetable specified by the Act, with polling day in late January 2025, the election campaign will run right through Christmas 2024 – a prospect many candidates would probably not welcome, let alone voters.

The Prime Minister is perhaps more likely to exercise his right to choose the date and call an election before the clock runs out, with polling day possibly in late autumn.

Under this scenario, Mr Sunak could use the next Conservative party conference, which would typically take place in late September or early October 2024, as a chance to launch his election campaign, with polling day set for late October or early November.

This would also give him a chance to reach his second anniversary of becoming prime minister, which falls on October 25 2024.

But if he decides to go to the polls even earlier in the year, an alternative date could be Thursday May 2, to coincide with local and mayoral elections in England.

Another possibility is early June, a month or so after the local elections – a pattern preferred by former Conservative prime minister Margaret Thatcher in 1983 and 1987.

Were polling day to take place in January 2025, it would mean the biggest interval between UK general elections since the Second World War.

The longest period is currently five years and 22 days, between the 1992 and 1997 general elections.

An election on either January 23 or January 28 2025 would beat this record, with a period since the 2019 general election of five years and 42 days or five years and 47 days respectively.