Wes Streeting is to double down on his calls for the UK to rejoin the EU despite warnings from Red Wall Labour MPs that he would lose votes to Reform.

Launching his bid to be prime minister on Saturday, the former health secretary said Brexit was a “catastrophic mistake” and that he wanted to see the UK “one day back in the European Union”.

Allies of Streeting told The i Paper that 10 years on from the EU referendum, a majority of Britons were now in favour of rejoining the bloc, and that the MP for Ilford North was “unafraid to make the argument and to lead people rather than follow”.

Culture Secretary Lisa Nandy, who is close to Streeting’s leadership rival Andy Burnham and whose Wigan constituency is in the Red Wall, warned against the party “reopening the Brexit wars”.

And a fellow Red Wall MP described Streeting’s calls as “pie in the sky”, telling The i Paper that Labour needed to focus on what it could achieve in government in the three years before the next election.