Financiers rather than contractors were the main focus of the latest attack.

The committee accused most PFI investors of avoiding tax by running their investments from off-shore havens.

Chair Margaret Hodge said: “We have seen information which strongly suggests that investors are making excessive profits from selling on shares in PFI projects.

“However, the Government currently lacks sufficient information on the returns made by investors, who have been able to hide behind commercial confidentiality.

“The Government should extend freedom of information to private companies providing public services and should introduce arrangements for sharing equity gains.

“The Treasury assumes tax revenues when assessing the value for money of a PFI project, yet does not monitor whether taxes are paid.

“In our evidence we found that tax revenue is being lost through the use of off-shore arrangements by PFI investors.”

The committee called for a return to traditional procurement but business chiefs stressed that PFI was often the only way of getting things built in the current economic climate.

Dr Neil Bentley, CBI Deputy Director-General, said: “Given the current state of the public finances, private finance must be an option if the we are going to see major new investment in infrastructure at an affordable price.

“What investors need now is a clear statement from the Government about how the use of private finance will evolve.”