Election 2024: What happens when you become Prime Minister?

If the polls are to be believed, the UK could get a new Prime Minister with Sir Keir Starmer taking the keys to Downing Street.

But whoever becomes the Prime Minister will have a packed schedule from minute one, with priorities including selecting a cabinet and setting the tone for the new government.

With vote counts not starting until the polls close at 10pm tomorrow, the picture is unlikely to become clear until Friday morning, though key early results will begin to spell out whether Labour is headed for its forecast landslide. 

There will, however, be an exit poll released at 10pm which will give an estimation of the night’s results. While this poll won’t be completely accurate, the scale of the forecast Labour majority means that, if the exit poll predicts a Labour win, this headline figure is unlikely to be proved wrong later in the night. 

Here’s City A.M.’s guide to a Prime Minister’s first duties once elected, including meeting the King and instructing nuclear submarines. 

Rishi Sunak needs to win his own seat

As well as their party winning a majority in parliament, a leader must also win in their own constituency to become Prime Minister.

Sir Keir Starmer’s seat, Holborn and St Pancras, is expected be called at 4:15am, and the Labour leader is projected to take a healthy majority.

Rishi Sunak’s Richmond and Northallerton seat, which could be called at 4am, will be a tighter race.

Though Sunak won the Tories’ largest majority in 2019, pollsters are divided over the PM’s future in parliament. Savanta marked the seat “too close to call” but projected a Labour win, while other polls have tipped Sunak to hold the constituency. 

Both these seats will be called relatively late on in the night, when an early indication of results will have already become apparent. 

Does a defeated party leader resign?

Whether Labour wins as forecasted or the Tories pull off a shock turnaround, the leader of the defeated party could resign on the day of the results.

Keir Starmer has already promised to step back if Labour loses, but Sunak has refused to confirm whether he would resign.

When pushed, he told the BBC’s Chris Mason: “Look, my priority is focused on this election. I love this party dearly, and of course I’ll always put myself at the service of it, and the service of my country.”

Some reports have suggested that Tory figures would prefer a defeated Sunak to stay on as leader of the opposition for a few months. Supporters of Kemi Badenoch, for example, reportedly prefer a December leadership contest, to allow them time to build the business secretary’s profile. 

If the results see an opposition head roll, however, this resignation is likely to come on Friday.

King Charles appoints the new Prime Minister

A visit to see King Charles is first on a newly-elected Prime Minister’s agenda. This would see the new PM visit Buckingham Palace to ask the King for his formal permission to form a government. 

This procedural requirement is one of the monarch’s various roles in the election cycle, as Sunak had to ask his permission to dissolve the government and call a snap election back in May. 

First speech as Prime Minister

After meeting with the King and formally being appointed, the new PM will take to a podium on Downing Street to deliver their first speech, celebrating the victory and setting out their key priorities for the government. 

The new Prime Minister will then enter No 10, and will be clapped through the door by staff, before meeting with the cabinet secretary, the UK’s most senior civil servant.

This office is currently held by Simon Case, whose responsibilities include advising the PM and ensuring the efficient running of government. 

Briefing on government priorities

The cabinet secretary, alongside other senior members of the civil service, will then brief the PM.

They will discuss key policy priorities, as well as living arrangements for the Prime Minister and their family.

Last month, Starmer confirmed that he will live in No. 10 with his wife and children, as per tradition, if elected as PM.

The new PM will also discuss the process of appointing their cabinet, as well as the protocol for emergency decisions, and security and intelligence information.

Nuclear letters

A key first duty of the new Prime Minister will be to write letters of instruction to the commanders of Britain’s four nuclear submarines.

These memos, known as “letters of last resort,” will dictate how the commanders respond in the event of a nuclear strike on the UK. 

Before writing this letter, the new PM will receive a briefing from the civil service on Trident, Britain’s nuclear deterrent.

The penning of the nuclear letters has been described by Whitehall historian Lord Hennessy as “the moment when they know what being Prime Minister is all about”. 

Forming a government

The Prime Minister will then appoint their cabinet ministers. Typically, the PM would meet individually with each minister in No. 10. 

While Keir Starmer already has a shadow cabinet in place, he may make changes to his lineup of ministers when forming his government, should Labour win the election. 

The key figures of Starmer’s shadow cabinet are likely to stay in place, which would see Rachel Reeves become chancellor and Angela Rayner take up the post of Deputy Prime Minister. 

Speaking with international leaders

After being briefed by the civil service, the new Prime Minister will then enter multiple rounds of phone calls with international leaders. 

Should Starmer become PM, he will want to use these phone calls to establish strong relationships with the UK’s rivals. The Labour leader has been attacked by some pundits for a weak foreign agenda. 

Earlier this week, Starmer said he would work with Marine Le Pen’s far-right National Rally should they win in France, but told reporters that the party’s success is proof that Labour must make a “progressive case” in Europe and across the world. Starmer has also said that he would work with Donald Trump, should he win the US election later this year. 

The new PM will also get the chance to announce himself on the international stage at various summits scheduled for later this month, including NATO in Washington DC and the European Political Community at Blenheim Palace. 

These first duties, likely to take place in the 72 hours following the election, will offer a fast-paced introduction to No. 10 for the new prime minister. 

The new PM’s duties for the rest of July and beyond will include the King’s Speech, initial legislation for the party’s headline policies, and the first budget of the new government, likely to come in October.