Keir Starmer will tell his party it must be New Labour “on steroids” and that he does not care if it “sounds conservative”.
In a speech on Saturday morning, the Labour leader is expected to say while the party is on the path to power the “toughest part lies ahead”.
Labour gained hundreds of council seats in last week’s local elections, which saw voters give Conservatives a kicking.
The results suggest Rishi Sunak is likely to be booted out of Downing Street at the next general election, expected to be held in 2024.
But Starmer could have to settle for Labour being the largest party in a hung parliament rather than winning an overall majority.
Speaking to the Progressive Britain annual conference in London, Starmer will say it “misses the point” to think all he is doing is distancing himself from Jeremy Corbyn’s “regime”.
“This is about taking our party back to where we belong and where we should always have been. Back doing what we were created to do,” he will say.
“That’s why I say this project goes further and deeper than New Labour’s rewriting of Clause Four.
“This is about rolling our sleeves up, changing our entire culture – our DNA. This is Clause Four – on steroids.”
Tony Blair famously scrapped Labour’s commitment to mass public ownership in 1995 as he sought to appeal to middle England.
Since taking over as leader in April 2020, Starmer has steadily moved Labour towards the political centre ground.
He has been criticised by those on the left of the party for abandoning many of the promises he made during the leadership campaign to stick to policies included in its 2017 and 2019 manifestos.
Last week, on the eve of the local elections, he all but confirmed his promise to to scrap university tuition fees would be ditched.
Plans to nationalise railways, Royal Mail, energy companies and water companies have been essentially scrapped, with Starmer having argued the economic situation now meant this was too expensive.
Progressive Britain is associated with the Blairite wing of the party and was formed in 2021 by the merger of the Progress and Policy Network groups.
Starmer will tell party members at the gathering that “I don’t care” if he “sounds conservative” sometimes.
“Somebody has got to stand up for the things that make this country great and it isn’t going to be the Tories,” he will say.
“That in the end is one of the great failure of the last 13 years. A Tory Party that in generations past saw itself as the protector of the nation and the union has undermined both.
“They’ve taken an axe to the security of family life, trashed Britain’s reputation abroad, and totally lost touch with the ordinary hope of working people.”
The suggestion Labour could fall short of a majority has led to questions about whether Starmer would do a deal with Ed Davey’s Lib Dems in order to become prime minister.
Starmer last week refused seven times to rule out forming a coalition with the Lib Dems, although he has said he would not do so with the SNP.