Andy Burnham is heading to No10 within days.
The former Greater Manchester Mayor is currently the only candidate to succeed Sir Keir Starmer as leader of the Labour Party and Prime Minister.
After nominations opened on Thursday for the Labour leadership contest, London and other MPs rushed to back Mr Burnham.
Brent West MP Barry Gardiner said he was the first MP through the door of the Parliamentary Labour Party office in the Commons to officially put his name to Mr Burnham’s papers to be leader.
Former Cabinet minister Mr Burnham declared his intention to stand for the leadership shortly after Sir Keir announced his resignation in an emotional speech in Downing Street on Monday, June 22.
It comes after Mr Burnham secured his path back into Westminster by sweeping to victory in the Makerfield by-election on June 18.
Could anyone still challenge Burnham?
Former Health Secretary and Ilford North MP Wes Streeting, who was seen as Mr Burnham’s main potential rival, ruled himself out of the contest shortly after Sir Keir announced his resignation.
Former armed forces minister Al Carns, who was seen as another possible challenger, has also given Mr Burnham a clear run to be Labour leader and PM.
Unless there is a surprise intervention, Mr Burnham is set to be the only candidate to take over at the helm of the Labour Party and gain the keys to No10.
Some Labour MPs still harbour doubts over a “coronation” as it means Mr Burnham’s plans for government have not been tested or scrutinised.
But his fast track to No10 avoids months of Labour infighting and political instability for Britain.
When will Burnham become leader?
Mr Burnham is set to become Prime Minister on July 20 when he is due to meet the King and be formally invited to form a Government.
Before then, the process for MPs to nominate candidates for the Labour leadership is due to close on July 15.
If no other candidates step forward, the 56-year-old Everton fan is expected to be formally declared Labour leader at a special conference on July 17.
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But it is understood he would not become Prime Minister immediately, with the formal handover taking place on the next working day, July 20, in line with the party’s previous practice.
Leadership hopefuls need to secure the support of 81 Labour MPs and at least three of Labour’s affiliated organisations by July 16 to get onto the ballot.
Who will be in Burnham’s first Cabinet?
Mr Burnham is continuing to mull his Cabinet picks.
Rachel Reeves is widely expected to be replaced as Chancellor, with several senior ministers including Home Secretary Shabana Mahmood and Energy Secretary Ed Miliband reportedly in the running to succeed her.
Former Transport Secretary Louise Haigh, MP for Sheffield Heeley, Labour Deputy Leader Lucy Powell, MP for Manchester Central, Culture Secretary and Wigan MP Lisa Nandy, and Knowsley MP Anneliese Midgley are all expected to get key roles.
Peckham MP Miatta Fahnbulleh, former Lewisham East MP Heidi Alexander, the current Transport Secretary, and Mr Streeting are also touted to get Cabinet positions.
London MPs who could be moved from their current Cabinet posts include Health Secretary James Murray, Communities Secretary Steve Reed and Justice Secretary David Lammy.