Plans to more than quadruple the size of NHS Scotland's private finance initiative programme risk creating a deficit crisis akin to that in England, researchers have warned.

Research from the Edinburgh-based Centre for International Public Health Policy says if plans for 23 new PFI hospitals go ahead, annual payments will increase from£107m to almost£500m.

Researchers Mark Hellowell and Professor Allyson Pollock claim the scale of charges will create an 'affordability gap' which will increase the need for service cuts and land sales.

Pointing to the correlation between English hospital trusts with large PFI commitments and deficits, they warn that a similar situation could emerge in Scotland.

At present, Scottish health boards lease£602m worth of hospitals through PFI schemes.

The researchers say: 'It is clear that the high cost of PFI, and the huge increase in its scale that is envisaged, will place a burden on the non-PFI parts of the NHS estate and provide pressure for closure of services within them.'

The two health boards with the biggest PFI commitments have serious underlying overspends - around£16m at NHS Lothian and£22m at NHS Lanarkshire, the researchers found.

The research came as the governing Scottish National Party pressed ahead with plans to develop an alternative to PFI in the form of a government bond scheme.

Scottish health secretary Nicola Sturgeon said: 'The Scottish government is very concerned about the cost to taxpayers and frontline services of PFI projects; that is why we are already examining an alternative system of infrastructure funding.'

The bond scheme would be run by a new Scottish Futures Trust which would effectively aim to borrow at the government rate of around 3.5 per cent, as opposed to the private sector rate of around 7-8 per cent.

Current PFI contracts would not be affected and it is not clear whether those currently under negotiation could be switched to the new scheme.