If he becomes PM, Burnham has already ruled out an early election, telling an online forum last week: "I'm going to work to the 2024 manifesto."

By September at the latest, the UK will have had seven prime ministers in the past decade.

Four prime ministers took over mid-term without having fought and won a general election: Theresa May in 2016, Boris Johnson in 2019, and Liz Truss and Rishi Sunak, both in 2022.

In each of these cases, there have been questions from opposition parties about their legitimacy in office.

But the next prime minister, like their predecessors, is under no obligation to call a general election before the scheduled end of the Parliament in 2029.

The current system sees the electorate vote for their MPs and a party, and those MPs and that party choose their leader.

The last general election was held on 4 July 2024, with Labour winning a landslide majority, meaning the next election must legally be held by August 2029, though a prime minister can choose to call one at any point before this.

A PM calling an early election depends on a number of factors - how the party is performing in the polls, and whether the prime minister wants to seek a new mandate from the electorate to set out his own agenda in government.

So while Burnham has ruled out an immediate election, there may still be one before the end of 2029.