Economist John van Reenen from the London School of Economics admits Labour’s policies may raise costs for employers but says the changes could also improve productivity, meaning companies will earn more per worker.

Shadow Chancellor Rachel Reeves claims greater security for workers and boosting growth are “two sides of the same coin”.

“There’s now a mountain of evidence that greater security at work and better wages lead to a more motivated and a more productive workforce,” she told The Telegraph.

“Building on what the last Labour government did with the first ever introduction of a national minimum wage, we will go further and turn that into a real living wage.”

However, there are signs of tension about these labour market plans even within the party.

Peter Mandelson, who helped guide Labour to a landslide victory with Tony Blair in 1997, used several speeches at the Labour conference in Liverpool last week to warn his colleagues against going too far.

“As we reform labour market policy and legislation, we have got to take care that we don’t reintroduce rigidities or trade union prerogative,” he told a fringe event, saying the party must be wary of empowering “those wonderful massive strike funds so beloved of Len McCluskey and Sharon Graham and one or two others”.

Wholesale reforms risk putting off international investors too, he said.

Unite general secretary Graham, meanwhile, accused Mandelson of being someone who would have resisted the creation of the NHS in 1945 and said Labour under Starmer was “too timid”.

Reeves insists: “Labour is a proudly pro-worker party. It is how we were created, it’s in our DNA. But we are also proudly pro-business because you can’t be pro-worker unless you’re pro the businesses that create the jobs and the wealth and prosperity.”

Just how sustainable that position is, will be put to the test as the election draws nearer.