British Prime Minister Keir Starmer will become the first UK leader to address the annual meeting of Britain's trade unions in 15 years on Tuesday.
Starmer's Labour party is billing the speech as a powerful symbol that the centre-left party is back in government after nearly a decade and a half of Conservative rule.
Labour has historically been allied with trade union organisations, which contribute a substantial amount to the party's income.
The Trade Union Congress (TUC), the umbrella body of 48 member unions comprising more than 5.5 million working people, helped found Labour in the early 20th century.
Gordon Brown was the last premier to deliver a speech to its conference in 2009.
Starmer, 62, is set to tell TUC delegates in the seaside resort of Brighton that he "will champion unions and business to come together" to refire Britain's economy, according to excerpts of the speech released by Labour.
"Partnership is a more difficult way of doing politics," the prime minister was due to say, seeking to draw a line under years of industrial unrest and tensions between unions and government.
"I know there's clarity in the old ways, the zero-sum ways: business versus worker, management versus union, public versus private. That kind of politics is not what the British people want."
Starmer will repeat his mantra that the Conservatives left Labour with a dire economic inheritance when they vacated office following a landslide election defeat in early July.
He was also due to warn that "the road to fixing the foundations of the country won't be easy".
Labour came to power pledging to end the waves of strikes that blighted the country in sectors from the railways to hospitals in the last few years of Tory rule.
It has announced above-inflation pay rises for public sector workers such as teachers and doctors and struck a pay deal with train drivers to pave the way for renationalising the railways.
Labour has also laid out proposals to legally ban practices such as "fire and rehire" -- where employers let workers go in order to rehire them on contracts with inferior terms -- and to ban zero-hours contracts, which leave workers without a minimum number of hours to be worked.
The TUC has welcomed the pay deals as a "crucial first step" but tensions are already emerging between some major unions and the new government.
The disagreements are in part caused by finance minister Rachel Reeves's promise of imposing "iron discipline" over public finances to claw back what she says is a £22-billion ($28.8-billion) black hole inherited from the Tories.
Two major unions have called on Starmer to reverse his government's decision to scrap winter fuel benefits for 10 million elderly people.
Unite boss Sharon Graham accused Labour of opting to "pick the pocket of pensioners" while leaving the richest "totally untouched".
Rail, Maritime and Transport (RMT) union general secretary Mick Lynch said the government was making a "historic mistake".