Small print of Budget reveals costs of PFI projects to rise to £10bn a year

The Government will have to pay £10bn a year to companies under the much-criticised Private Finance Initiative (PFI), according to new estimates buried in last week's Budget.

Under previous forecasts, no more than £9.5bn a year has come out of the public purse. However, the Government will pay between £10.05bn and £10.53bn in 2014 and 2018.

The PFI sees private sector consortiums build and run major public infrastructure, including schools and hospitals. The consortium raises the money for the project, while the government pays it back plus profit over the contract, typically 25 to 35 years.

Unions, which largely view the PFI as a form of privatisation, were infuriated by the increases. Paul Maloney, of the GMB union, said: "I would like to know exactly where all this money is going. This raises an issue, but does not answer any questions."

A Treasury spokesman said that inflation, revised contracts and new contracts had increased the costs.