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.