Andy Burnham will promise a new path for Britain in a speech as he becomes the new Labour leader on Friday.

The Makerfield MP will be confirmed in the role at a special party conference in central London, ahead of taking over from Sir Keir Starmer as prime minister on Monday.

In his speech, Burnham will say that when he is in Downing Street, the government will be “unashamedly Labour in our priorities” and have the “courage to fix the big things that politics has neglected”.

Burnham cemented his status as the sole leadership candidate after being backed by 379 Labour MPs and most trade unions linked to the party earlier this week.

Home Secretary Shabana Mahmood, in her role as the chair of Labour’s ruling national executive committee, will announce Burnham as the new leader at the conference.

It will mark a rapid rise to power following the former Greater Manchester mayor’s by-election win in Makerfield last month.

Making the economy work for people across the UK will require a “new path to the one we’ve been on for the last 40 years”, Burnham will say.

In his first speech as Labour leader, he will also say that the Labour government will be “focused on driving growth in every postcode and returning power to communities” when he becomes prime minister.

He will say the government will have the “conviction to argue for our plans”.

Promising a “distinctively Labour” programme of economic policies, Burnham will say his plans involve more public control of utilities such as water, and reindustrialisation.

Labour, he will say, will be more united under his leadership and more open to working with other parties on the long-term challenges facing the country.

He will commit to being a leader “for the north and the south, for Scotland, for Wales and for Northern Ireland, and for every town and every city in every nation and region of this great country”.

He will also pay tribute to Sir Keir for winning the general election in 2024 and point to NHS improvements and investment in public services as achievements of the Labour government so far.

Sir Keir resigned as Labour leader last month, saying he accepted he was not best placed to lead his party into the next general election.

Heavy Labour losses in May’s local elections followed by Burnham’s by-election victory in Makerfield had left Sir Keir facing widespread calls from his own MPs for him to stand aside and allow Burnham to replace him.

When potential leadership contenders Wes Streeting, the former health secretary, and Al Carns, a former defence minister, said they would not challenge Burnham, it paved the way for him to become the next prime minister unopposed.

Sir Keir has said he will support his successor and offer him advice privately, if asked.

Speaking to Sky News during a visit to Ukraine on Thursday, he said he wanted an “orderly transition” and that he had built a “sound foundation” for Burnham.

His successor has given little detail about his policy plans and has not announced who will be appointed to key cabinet roles.

Announcements on cabinet posts are not expected to be made until Monday, when Burnham takes office in Number 10.

But multiple reports suggest Shabana Mahmood could be Burnham’s pick for chancellor, with the BBC told there are “live discussions” over this.

On policy, Burnham offered some details about his blueprint for office in a speech in Manchester earlier this month.

He proposed a new No 10 unit in Manchester, where a team would be tasked with handing local government more control in areas including housing and transport.

In the early weeks of his premiership, Burnham is planning to undertake a “listening tour” of the UK while Parliament is in recess this summer.

Burnham has signalled that providing extra support for the cost of living will be one of his priorities in government.

He has defended his credibility on economic policy, insisting he will not be “indisciplined” with the public finances.

But the International Monetary Fund (IMF) has warned Burnham’s incoming government to avoid increasing public spending in the face of pressures such as rising household energy bills.

In a new report on the UK, the IMF said the UK should try to stay focused on its plans to grow the economy.

“This calls for a cautious approach to new fiscal pressures: the authorities should be very selective in accommodating new demands and reprioritise, while sticking to the deficit reduction plan,” the report says.

“Future spending reviews should focus on reallocating resources across departments, rather than increasing total spending.”