Critics have suggested, however, that they simply move economic activity or jobs from one part of the country to another, rather than creating new opportunities or roles.

Sir Keir said “that’s why we would do well to make some tweaks to freeports to make sure they work in their own right”.

He said Labour wanted to see growth plans “for every area, every place” drawn up by mayors, local authorities and local businesses, “so freeports don’t sit on their own as the only source of jobs and investment in a given area”.

He also said that a new investment zone in the East Midlands, which will aim to boost high tech green industry, was “really important”.

There are already two investment zones in the UK, which apply to specific local areas and see firms offered financial incentives.

“These zones attract investment, and they’re measured in tens of thousands of well-paid jobs, so this is really good news,” Sir Keir said.

He added that economic growth is the “number one mission of this government”.

However, the watchdog that looks at the government’s finances, the Office for Budgetary Responsibility predicted in 2021 that tax breaks in England’s freeports would cost the UK government £50m a year.

It said that historical evidence suggests their “main effect” would be to move economic activity from one place to another.

Internationally, freeports have also been linked to organised crime, money laundering, smuggling, and low wages, the Scottish Greens argued in 2023.

But according to the government, freeports in the UK have attracted £2.9bn of investment and created an estimated 6,000 jobs.