SENIOR Labour MP John McDonnell said he is “beginning to believe in the powers of conversion” after Labour leadership hopeful Wes Streeting came out in favour of a wealth tax today.

The former shadow chancellor mocked the ex-health secretary’s Road to Damascus moment as he addressed PCS’s annual conference in Brighton.

Referring to Mr Streeting’s controversial defence of US tech firm Palantir’s NHS contract, Mr McDonnell said: “Wes Streeting tried his [leadership] coup last week — that failed so the right honourable member for Palantir is now, today, coming out in favour of a wealth tax.

“I was brought up a Catholic, and if Wes Streeting can now advocate a wealth tax I’m beginning to believe in the powers of conversion again.”

Mr McDonnell added that the Labour Party’s policy director under Jeremy Corbyn’s leadership, Andrew Fisher, now PCS policy officer, “will be really pleased with this — that in Wes Streeting’s speech to Parliament yesterday he called that the Labour Party should be for the many, not the few. Where did you hear that before?”

On embattled PM Sir Keir Starmer, the veteran left-wing MP told delegates that comparisons to Liz Truss’s short-lived premiership — which was infamously outlasted by a lettuce — were “unfair.”

“He’s from Camden — he’s most like the overripe avocado,” quipped Mr McDonnell, who added he hoped Greater Manchester mayor Andy Burnham beats Reform UK in the upcoming Makerfield by-election.

“The Labour Party are doing everything it can to ensure that he doesn’t win but if he does I think it’s highly likely that there will be a leadership change,” said the Hayes and Harlington MP.

Mr McDonnell, who chairs PCS’s parliamentary group and received a standing ovation, said that “it is beyond me” how outsourcing giant Capita has continued to receive government contracts.

The government announced in March that Capita was to be awarded the Synergy contract to administer payroll, HR, finance and other backroom functions for around 250,000 civil servants.

PCS general secretary Fran Heathcote told the Morning Star that Labour’s pre-election vow for the “biggest wave of insourcing in a generation” was not “even a ripple” and that Capita’s track record shows “they are just not going to be able to deliver,” costing the taxpayer more in the long-run.