Keir Starmer was yesterday elected leader of the UK Labour Party, pledging to bring an end to years of bitter infighting and to work with the government to contain the raging coronavirus pandemic.
Starmer, a former director of public prosecutions who was known for a forensic attention to detail when opposing Brexit, won with 56pc of the vote.
The comprehensive defeat of an ally of outgoing leader Jeremy Corbyn, and the election of Angela Rayner as Starmer's deputy, heralds the end of the party leadership's embrace of a radical socialism crushed in December's UK general election.
Starmer, who takes over immediately, said he would work constructively with government when it was the right thing to do, while testing UK prime minister Boris Johnson's arguments and challenging the failures.
"Our purpose when we do that is the same as the government's, to save lives," he said.
Starmer added that once the country emerges on the other side, once the hospital wards have emptied and the threat subsided, it would need to build a fairer society, in which key workers on the frontline receive decent salaries and better chances in life.
Johnson said on Twitter he had congratulated Starmer and the two agreed on the importance of working together.
The party of Tony Blair and Gordon Brown endured its worst election performance since 1935 in December, when infighting over strategy, a confused policy over Brexit and allegations of unchecked anti-Semitism turned traditional voters away.
Starmer pushed for a second Brexit referendum but said the election result had "blown away" that argument.
Corbyn ally Rebecca Long-Bailey came second in yesterday's vote with 28pc and Lisa Nandy third with 16pc.
Many centrist Labour politicians celebrated the result as a sign the government would finally face proper scrutiny.
Well ahead in opinion polls, Johnson's Conservatives have also occupied much of traditional Labour territory, with the coronavirus crisis prompting the ruling party to deliver unprecedented state support to workers and businesses.
Starmer is 5/2 favourite to become the next prime minister, according to Ladbrokes.
In another sign of a power shift in the party, three candidates seen as Blairite won seats on the party's National Executive Committee.
Starmer, who served as head of the Crown Prosecution Service and accepted a knighthood in 2014, has struggled to shake off perceptions of privilege. But he has stressed his upbringing by his toolmaker father and nurse mother in Southwark, south London, when dismissing allegations he is too middle-class to speak to the party's historic heartlands.
His CV includes advising the Policing Board to ensure the Police Service of Northern Ireland complied with human rights laws.
He entered parliament as MP for Holborn and St Pancras in 2015 and was quickly elevated to the front bench, serving as a shadow Home Office minister before being promoted to shadow Brexit secretary soon after the EU referendum in 2016.
Starmer was instrumental in getting Labour to back a second referendum. He has since said the issue is settled, but refused to rule out campaigning for Britain to return to the EU in the long term.
The leadership contest was triggered in December when Corbyn announced he would quit as Labour leader.
He had presided over years of factional fighting, accusations of institutional anti-Semitism and bitter divisions over Brexit.
The veteran left-winger became party leader in 2015, a result which marked a fundamental change of direction for Labour.
He led the party through two general election defeats, the last of which saw seats which had been Labour for generations turn blue as the party's hitherto impregnable "red wall" crumbled in the face of the Tory advance.