The MP for Makerfield cemented his status as the sole leadership candidate after being backed by 379 Labour MPs, as well as all 11 trade unions affiliated to the party, earlier this week.
Having run twice before to become Labour leader, his successful bid this time round marks a rapid rise to power following the former Greater Manchester mayor’s by-election win in Makerfield last month.
In his first speech as Labour leader at the TUC headquarters in central London, Burnham rejected the “neoliberal” policies of the past 40 years, including when he was in government, and vowed to reindustrialise the country.
Promising to lead a government that is “distinctively Labour,” he said: “Britain took a series of wrong turns in the 1980s – political power was centralised and economic power was privatised.
“The country surrendered control of the essentials.”
And in a message to Labour MPs, he said he would work relentlessly to build a culture of “one Labour team”.
“We won’t beat Britain’s new right if we are consumed by infighting and pulling in different directions,” he said.
He added that his approach to governing would be characterised by “problem-solving rather than point-scoring”.
Having run twice before to become Labour leader, his successful bid this time round marks a rapid rise to power following the former Greater Manchester mayor’s by-election win in Makerfield last month.
Labour has trailed Reform UK in opinion polls for almost 18 months and supporters will be hoping Burnham’s arrival as prime minister will reverse their fortunes.
Burnham has given little detail about his policy plans and announcements on cabinet posts are not expected to be made until Monday when he takes office.
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.
