Industry sources have said that changes to PFI refinancing rules, which mean contractors profit less from deals, will only have an immediate impact on schemes that date from the mid to late nineties.

One source said: 鈥淔or refinancing to be worthwhile you have to go back to schemes from the nineties when interest rates were two or three percentage points higher.鈥�

Since then interest rates have dropped, so refinancing schemes built more recently would not generate much profit, sources claim.

Under new rules, investors would receive 30% of any profit on refinancing, compared with a previous 50-50 split with the government. The new terms, which provide a potential extra cash source for the public sector, apply to gains over 拢3m.

Rob Pfitzner, senior legal manager at Bouygues said: 鈥淲hat will be important for us is making sure there is an adjustment back when the markets normalise.鈥�??