Andy Burnham has taken over Labour – but when does he actually move into Number 10?

Well, it's official! Andy Burnham is now the leader of the Labour Party after being elected without anyone attempting to challenge him, but he's still not yet the UK's Prime Minister. So, who is?

Although Keir Starmer has now had his last ever PMQs, given his final interview as Prime Minister from Ukraine (in which he said he's proud to be leaving the country in a better state than when he inherited it) and Burnham has formally taken over the party, the constitutional transfer of power has not happened yet. Starmer will remain as Prime Minister on paper until he formally tenders his resignation to King Charles.

Here's everything we know about when Burnham is expected to move into Number 10, who'll technically be Prime Minister over the weekend, and what happens next...

Andy Burnham officially became Labour leader on Friday 17 July after winning the contest unopposed, making him Prime Minister-in-waiting rather than Prime Minister himself.

However, becoming leader of the governing party doesn't automatically make someone Prime Minister.

Instead, there has to be a formal constitutional handover, which involves King Charles and everything. First, Keir Starmer must first travel to Buckingham Palace to tender his resignation to the King, who will then invite Burnham to officially form a government, before Burnham returns to Downing Street to deliver his first speech as Prime Minister.

That process is expected to happen on Monday 20 July.

That'd be Sir Keir Starmer. Even though Andy Burnham is now Labour leader, Starmer remains Prime Minister until the formal transfer of power at Buckingham Palace on Monday.

That means Starmer is still responsible for the government over the weekend, despite having completed his final media interviews and effectively entered the final days of his premiership. Only once he resigns to the King and Burnham is invited to form a government will the office officially change hands.

Even when the governing party changes leader, the office of Prime Minister doesn't automatically transfer at the exact same moment, because of the constitutional process above.

It's the same process that saw Liz Truss succeed Boris Johnson in 2022, and Rishi Sunak replace Truss later that year.

In his resignation speech outside Number 10, Starmer acknowledged he'd lost the confidence of enough Labour MPs to continue leading the party and when speaking to Sky, said he chose to step aside to avoid a "massive fight" inside Labour that could destabilise the government.

"I felt that it was right to apply the same principles I've always applied, which is, what is in the best interest of the country?" he told journalist Beth Rigby. "How do I ensure that we don't implode into some massive fight in government?"

Starmer said ensuring a smooth transition was in the national interest and stressed that an orderly handover remained his priority.

Starmer is expected to remain an MP after leaving Downing Street. There has also been speculation he could return to frontline politics in a different role, although no future position has been confirmed.

If Burnham is appointed Prime Minister on Monday 20 July, he'll have only a short period before Parliament rises for the summer recess (AKA school holidays for MPs).

That means he'll only have a short time to make statements in Westminster before it closes until September. The compressed timetable has already prompted criticism from opposition politicians, who argue the new Prime Minister should face greater scrutiny before being made the most powerful politician in the country.

Now that Burnham has officially become Labour leader, attention has shifted to Monday's constitutional handover and the announcement of his first Cabinet. Reports suggest he'll unveil much of his ministerial team as he enters Number 10, alongside further details about how his government will operate and when plans such as 'Number 10 North' will begin taking shape.

Burnham has long argued that too much political power is concentrated in Westminster and a big part of his approach is centred on devolution (giving local mayors more power to decide what works for their communities). This new northern office could become a base for ministers working on regional growth, transport, housing and devolution, and is designed to symbolise his wider pledge to shift decision-making away from Whitehall.

If he becomes Prime Minister, Burnham is still expected to have the use of the official Prime Ministerial residence at 10 Downing Street in London. His proposed Number 10 North would function as an additional working office rather than a replacement home.

In practice, that means Burnham is expected to divide more of his working week between London and Manchester than previous Prime Ministers, while Downing Street remains the constitutional centre of government.

Jennifer Savin

Features Editor

 Jennifer Savin is Cosmopolitan UK's multiple award-winning Features Editor, who was crowned Digital Journalist of the Year for her work tackling the issues most important to young women. She regularly covers breaking news, cultural trends, health, the royals and more, using her esteemed connections to access the best experts along the way. She's grilled everyone from high-profile politicians to A-list celebrities, and has sensitively interviewed hundreds of people about their real life stories. In addition to this, Jennifer is widely known for her own undercover investigations and campaign work, which includes successfully petitioning the government for change around topics like abortion rights and image-based sexual abuse. Jennifer is also a published author, documentary consultant (helping to create BBC’s Deepfake Porn: Could You Be Next?) and a patron for Y.E.S. (a youth services charity). Alongside Cosmopolitan, Jennifer has written for The Times, Women’s Health, ELLE and numerous other publications, appeared on podcasts, and spoken on (and hosted) panels for the Women of the World Festival, the University of Manchester and more. In her spare time, Jennifer is a big fan of lipstick, leopard print and over-ordering at dinner. Follow Jennifer on Instagram, X or LinkedIn.