Sadiq Khan has been urged to ban London bus companies from using fire and rehire tactics by a leading trade union.

Unite, which represents transport workers across the country, has called on the current Mayor of London to ban employers that use fire and rehire tactics from bidding for future TfL contracts.

It follows a dispute between bus drivers in Manchester and the Go Ahead group, which also operates almost a quarter of London’s buses, over new contracts.

Unite has called on the current mayors of London and Manchester to take action against bus companies that “sack workers and then rehire them on inferior conditions”.

Sharon Graham, executive officer for Unite, said: “Today we are calling on Andy Burnham and Sadiq Khan to publicly back a declaration which bars employers who use fire and rehire from bidding for future contracts in the great cities of London and Manchester. Warm words in support of the bus drivers in Manchester who are under attack are simply not enough and workers in London could be next. It’s time to act.

“It’s obviously wrong for companies to sack workers and then rehire them on inferior terms and conditions. Workers need more than words of sympathy. While the government drags its heels, the Labour Mayors of Manchester and London must lead the way by using their powers to outlaw fire and rehire on their watch.”

Today, a London Labour spokesperson said that Sadiq Khan believes fire and rehire “is a completely unacceptable practice – as we’ve seen with British Gas just this week”.

The spokesperson said: “As Mayor of London, Sadiq established a Responsible Procurement Policy to ensure that the GLA uses its procurement to drive up pay and conditions in the companies paid to deliver services for Londoners.

“If re-elected, Sadiq is committed to reviewing that policy regularly to ensure we get the best possible deal for Londoners whilst creating sustainable, well-paid jobs.”

This week, almost 500 British Gas engineers lost their jobs after refusing to sign new contracts that would have increased their working hours and reduced their average pay.