Billions of pounds of public money has become "locked" into paying for expensive, privately financed school and hospital projects, landing taxpayers with huge bills for years to come, the public-sector union Unison warned yesterday.

Billions of pounds of public money has become "locked" into paying for expensive, privately financed school and hospital projects, landing taxpayers with huge bills for years to come, the public-sector union Unison warned yesterday.

The union said a new analysis of the private finance initiative (PFI) had forecast that projects across the UK currently valued at £64bn would actually result in a bill of more than £217bn in repayments by 2033/4.

It called for an end to the "bottomless pit" and argued that new PFI schemes should be replaced with publicly funded design-and-build plans.

Unison General Secretary Dave Prentis said: "Public projects have become tainted by private failure. PFI has been a long and wasteful experiment and it is time to bring it to a close. We should look forward instead to a more efficient, more flexible and ultimately more valuable way of building the schools and hospitals we need.

"The recession has put the final nail in the PFI coffin and publicly funded design-and-build schemes should be the future."

Prentis called on the UK government to bring existing PFI contracts back into public ownership, and criticised a special unit being set up to administer £2bn in funds to help bring stalled PFI deals to a financial close.

"Now that private finance has dried up, with bank lending almost halted, the Treasury is pumping £2bn into PFI schemes to prop up the private sector to keep the flow of deals," he said. "This is simply throwing good money after bad."

Unison's report claims that PFI consortiums continue to make huge profits at the expense of the taxpayer, on contracts that are inflexible, complex and often lead to poor design. PFI projects are also hugely complex and slow, and tie managers running hospitals and schools into inflexible 30-year contracts, it says.

It highlights the irony of PFI schemes that are supposed to be privately funded but, because of the collapse in banks and lending, have had to turn to the government for support. At the same time, the government has been forced into taking a stake in the same banks whose lending policies have caused the crisis and who in turn have been big lenders to PFI.

Unison said the collapse of London Underground contractor Metronet showed how the public sector had to bail out privately financed schemes. When Metronet went bust just four years into its £17bn, 30-year contract to modernise the Underground, it was the local-government body Transport for London that picked up the £410m bill.

Unison in Scotland has highlighted concerns over a number of PFI schemes, including car-parking contractors in Edinburgh whom it says wanted to charge the NHS £70,000 for recalibrating meters at Edinburgh Royal Infirmary when the VAT rate was cut.

A spokesman for the UK Treasury said: "Through PFI this government has signed off over 650 projects, of which over 450 are operational, delivering new hospitals, schools, transport schemes and local authority projects, the vast majority to time and budget."

The Scottish Government has opposed the use of PFI, but its own solution, the Scottish Futures Trust (SFT), has been heavily criticised. Last year Unison condemned it as "PFI-lite" and warned it would retain higher borrowing costs and excessive risk-transfer costs.

Dave Watson, Unison's Scottish organiser, said: "The SFT plan for a new giant private company to run all Scotland's future PFI schemes merely puts a gloss of accountability on a fundamentally flawed base."

Instead, Unison set out a five-point plan calling for a review of existing contracts; a freeze on the awarding of new contracts; the awarding of government capital grants equally to projects; the introduction of "prudential" borrowing for health boards; and better protocols to protect staff in any transfers.

Councils have increasingly become restive about the SFT, which has yet to deliver any major infrastructure investment, despite two years of planning.

A recent leaked report from the Convention of Scottish Local Authorities (Cosla) condemned the PFI alternative as "unfocused", "disappointing" and "not in any position to fund infrastructure investment". Many councils are now looking at ways of bypassing the SFT and devising "workable" ways of funding new schools.