Trade union Unison has backed a Labour MP’s call for a windfall tax on private companies delivering public services.

The union said the tax could be a ‘lifeline’ to the public sector and would mean that companies with private finance initiatives (PFI) with the public sector would have to pay back ‘billions’ of pounds they have earned through the partnerships.

Unison general secretary, Dave Prentis, said: ‘Local communities may now have shiny new schools and hospitals but at huge cost.

‘There’s no time to lose.

'Crippling PFI debts are pushing local services to the brink and costing taxpayers dear.

'It’s time for a windfall tax on the companies cashing in at our expense.

'It would bring some urgent and much-needed relief for the services we all rely upon.’

Last month, Walthamstow MP Stella Creasy suggested a windfall tax on companies delivering services in the wake of Carillion’s collapse.