Taxpayers have been saddled with a £330 million “mountain of debt” because Sussex's new hospitals were built with private cash, it was claimed yesterday.

The Liberal Democrats attacked the use of the controversial private finance initiative (PFI) for two NHS projects in the county, warning Labour's legacy would be “cuts in vital services” to pay the future bills.

According to an analysis by the Liberal Democrats, the two Sussex hospital schemes are worth a total of £58 million, but the eventual PFI payments will amount to £331 million – more than five times as much - because the hospital trusts involved did deals with private developers.

The biggest bill will be for the Royal Alexandra Children's Hospital, which was rebuilt at the main Royal Sussex County Hospital site in Eastern Road, Brighton, and reopened in 2007.

The deal to redevelop the hospital, whose construction costs came to £36 million, was struck in 2004 after the Brighton and Sussex University Hospitals Trust agreed to pay developers a total of £180 million over 30 years - a sum which also covered the cost of maintaining the building for the duration of the agreement.

Brighton and Sussex University Hospitals Trust, which runs the Royal Alexandra, yesterday refused to comment on the cost of the PFI deal.

Similarly, the reconfiguration of mental health services near the old Graylingwell Hospital in Chichester cost £22 million but taxpayers will pay £151 million over 30 years under a deal agreed by the Sussex Partnership Trust in 1999.

Norman Lamb, the Liberal Democrat health spokesman, said: "Hospitals all over the country are mortgaged to the hilt and there are serious concerns that these repayments will lead to cuts in vital services."

The criticism was echoed by the health union Unison, which said PFI had allowed big businesses to "make a killing" out of the NHS.

A Sussex Partnership Trust spokesman said the figures released by the Liberal Democrats were higher than the trust was paying and that all PFI schemes had to demonstrate they were good value for money and affordable.

A spokesman for the Department of Health added: "The cost to the public sector of undertaking long term capital investment has always been spread over a number of years - PFI is no different.”