Nearly a third of the new schools so far completed under the Building Schools for the Future programme were finished late, with many not opening for up to a year after the projected completion date.
Fifteen of the first 50 schools delivered through the Pounds 45 billion secondary schools renewal programme were overdue and nine of those were not opened until a year after originally scheduled, it has emerged.
The statistics came to light in a written answer to a parliamentary question tabled last week by Liberal Democrat MP Paul Holmes.
He told The TES: "The government always quotes that 88 per cent of PFI (private finance initiative) projects are finished on time and on budget, as opposed to 30 per cent of projects funded by local authorities. Well, the figures for the first 50 BSF schools paint a very different picture.
"Over 30 per cent of BSF schools were finished late, and so it means the 88 per cent figure the government keeps quoting is absolute baloney."
Just 17 days ago, schools minister Jim Knight celebrated the opening of Sedgehill secondary in Lewisham, the 50th BSF school. But it was originally meant to open in January 2008.
Similarly, Bridge Learning Campus in Bristol opened last month, but the amalgamated primary and secondary had been scheduled to open in April 2008.
A spokesperson for Partnerships for Schools, the agency overseeing the programme, denied any of the schools were delivered late. He claimed that the statistic "relates to the baseline targets for school openings that were agreed early in the programme, and against which the programme as a whole is measured".
He added: "These are different from the contractual dates agreed between local authorities and their private sector partner at financial close. On this latter measure, given that budgets are confirmed when contracts are signed, all schools were delivered on time and on budget."
The news places yet more strain on the BSF project, which is facing an uncertain future due to the lack of lending and unwillingness to take on risk in the PFI market.