Sir Keir Starmer has promised not to raise income tax if he wins the next general election.
The Labour leader said he would avoid hikes “across the board”, having previously ruled out a wealth tax on the richest in society.
He told the Mirror: “We will do nothing to increase the burden on working people, whether it comes to tax or anything else.”
Asked whether he would increase income tax, he told the paper: “No.”
Sir Keir has backed away from tax rises since pledging to increase income tax for the top 5% of earners during his 2020 leadership bid, instead emphasising his aim to secure the highest growth in the G7.
The leadership was criticised last month by the Labour left for its decision to rule out any kind of wealth tax if it wins the next election.
The move is designed to blunt Tory attacks, with figures concerned that the possibility of tax hikes or unfunded spending pledges would be used to paint the party as economically incompetent.
The plans echo those promised by Sir Tony Blair and Gordon Brown in the run-up to their 1997 landslide victory in 1997, when they pledged not to raise tax and to stick to Tory spending for the first two years.
Sir Keir is expected to use this year’s party conference to set out how a government led by him would revive a sluggish economy, with planning reforms central to the party’s bid to build its way back to economic growth.
It will take place on October 8-11, following the Conservatives’ conference to be held in Manchester on October 1-4.