Andy Burnham has tried to become Labour leader before - twice running, twice missing out.
But it may now be a case of third time lucky, with Sir Keir Starmer's resignation and many Labour MPs rallying around the new MP for Makerfield, paving the way for a potential Burnham premiership.
Burnham has confirmed he intends to bid for the leadership, and his chances will have been boosted by the backing of Wes Streeting - Sir Keir's former health secretary who had himself been keen on running for the top job himself.
Burnham's first major obstacle to the doors of Downing Street was cleared last week when he won the Makerfield by-election, seeing off a challenge from Reform UK, which came second but more than 9,000 votes behind Labour.
The former Greater Manchester mayor increased Labour's share of the vote from 45% at the 2024 general election to almost 55%.
Now the Labour MP, who was first elected to Parliament in 2001, will be sworn into Parliament on Monday afternoon. But how did he become front-runner in the race for No 10?
Born in Liverpool in 1970, Burnham grew up in Culcheth, a quiet commuter belt village in Cheshire, near Warrington.
His father, a BT engineer, and his mother, a GP receptionist, were both staunch Labour supporters and he developed an early interest in politics.
Burnham has described how he was inspired to join the Labour Party at the age of 14, after being moved by the BBC TV drama, Boys from the Blackstuff, about life on the dole in Liverpool.
A lifelong Everton fan, his friends remember Burnham as a competitive, sports-mad child, who was a fast bowler for Lancashire schoolboys cricket team.
At school, the local Roman Catholic comprehensive, his English teacher recalls how he stood to be a Labour candidate in mock elections - and won by a landslide.
Burnham and his two brothers were the first in their family to go to university, with Andy studying English at Cambridge.
In his book, Head North, Burnham wrote that he "struggled to feel part of things" at university and felt like an "imposter".
However, the music-lover - who is a fan of northern indie bands like The Smiths and The Stone Roses - said his "growing interest in Manchester music gave me an identity and an advantage".
After graduating, he started out in journalism, working for trade magazines including Tank World and Passenger World Management.
In his early 20s, he got his first break in politics, working as a researcher for the late Tessa Jowell, then MP for Dulwich and West Norwood, who would go on to be a minister under Tony Blair and Gordon Brown.
Despite his later contempt for Westminster politics, Burnham rose quickly through the ranks, becoming a special adviser to Culture Secretary Chris Smith before being elected as the MP for his hometown of Leigh, in Greater Manchester, in 2001.
He first served as a junior minister under Blair, but joined the cabinet as chief secretary to the Treasury, and later culture secretary and health secretary, under Brown.
It was as secretary of state for culture, media and sport that Burnham was heckled at a memorial service marking the 20th anniversary of the Hillsborough disaster.
Ninety-seven Liverpool fans were killed in the stadium crush of 1989.
The heckling spurred Burnham on to raise the issue in cabinet, contributing to the launch of a second inquiry into the disaster.
In 2010, after Brown resigned following Labour's general election defeat, Burnham ran to become the party's leader.
He came fourth out of the five contenders, losing to Ed Miliband, but spent the next five years building up his appeal with the party's grassroots.
In 2015 he tried again, beaten this time by Jeremy Corbyn.
Burnham's critics have branded him a weather vane, whose views have blown with the political winds to give him the best chance of success.
A Remain supporter during the Brexit referendum, he has expressed a desire to see the UK rejoin the European Union in his lifetime.
However, despite recently reiterating his belief that there is a case for rejoining "in the long-term", he has said he will not be advocating for this in the Makerfield by-election - which is taking place in an area which vote strongly for Brexit.
He served in Corbyn's shadow cabinet, as shadow home secretary, despite being seen as on the Blairite centre-right of the party.
Burnham's views have moved increasingly to the left, backing the nationalisation of water and energy.
He was not one of those who resigned in protest at Corbyn's leadership in 2016.
Instead he stood down in 2017 to run to be the first mayor of Greater Manchester.
Burnham won the contest with more than 60% of the vote and was re-elected by an even bigger margin in 2021.
As mayor, he has drawn praise for his transformation of the region's transport system.
Under his leadership, Greater Manchester was the first area outside London to bring bus services back under public control, while integrating them with other modes of transport under the branding of the "Bee Network".
Other bold pledges included ending rough sleeping in the region by 2020 - although the target was missed.
His profile rose further during the Covid pandemic, when he accused the Conservative government of treating the north of England with "contempt" over regional lockdown restrictions.
The stand-off helped earn him the nickname "King of the North".
By the autumn party conference season of 2025, Burnham was openly on manoeuvres for the top job, as he refused to rule out a leadership bid.
His interventions appeared to backfire, after he provoked a backlash by suggesting the government was "in hock" to the bond markets - a reference to the government's self-imposed rules limiting spending and borrowing.
In January a potential opportunity for a return to Westminster arose when Greater Manchester MP Andrew Gwynne announced he was standing down, triggering a by-election in his Gorton and Denton constituency.
However, Burnham was blocked from standing by Labour's ruling body, with the approval of the prime minister.
By May, the situation had changed. Labour suffered a poor set of election results in England, Scotland and Wales, with Reform riding high in the polls and the party seeing success in Burnham's backyard.
Sir Keir faced increased pressure over his future, with some MPs calling for change and ministerial resignations taking place.
Josh Simons announced he would step down as Labour MP for Makerfield to make way for Burnham to mount a bid to return to Parliament.
Burnham went on to be selected as the Labour candidate for the constituency and the following month he secured his return to Westminster.
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