Treasury officials struggled to put a figure on the nation’s PFI debt when they faced tough questions from a select committee of MPs.

Senior civil servants were given a rough ride when they faced the public accounts committee on Wednesday to discuss measures to improve the value for money of PFI service contracts.

Conservative MP Richard Bacon expressed angry surprise when Jeremy Pocklington, leader of the Treasury’s corporate and private finance team, could not give him a simple total of the debt in future years.

“I have been trying for many years to get to the bottom of how big PFI is”, Bacon, a former banker and financial journalist, said.

“You must know what that number is.”

An increasingly flustered Pocklington was badgered by an increasingly strident Bacon until, after much shuffling of papers and murmuring amongst the dozen or so Treasury juniors in the public seats, the official produced the budget report.

But that only provided the liabilities per year, not the total, and Pocklington said he could not add it up there and then.

But Bacon was clearly determined to have an answer to his question and said he would do it himself, whipping a calculator out of his pocket as he said so.

His fellow MPs were soon laughing out loud as Bacon made the civil servant read out the total for every year.

Even Pocklington, who had been looking extremely rattled, found the funny side of it.

And Bacon got something of an answer. The total liabilities, but not debt, from the vast majority of PFIs, but not all, from 2006-07 to 2032-33, but not beyond, is £157.9bn.

But that’s not definitive and it could be a different figure in a fortnight after committee chairman Edward Leigh told the Treasury officials they had two weeks to submit more accurate information.

Labour MP Austin Mitchell also took a combative approach to the session, concerned with the National Audit Office’s report on the relatively new measure of bench marking and market testing PFI service contracts.

He was convinced that the auditors survey of renegotiations and tenders showed “greedy capitalists” being allowed to “run rings” around local authorities, hospital trusts and other procuring authorities.

The MP said experienced private negotiators had a massive advantage over their inexperienced public sector partners and he likened the Treasury’s attempts to reign in the PFI sector to “desperately trying to hold a tiger by the tail”, but “basically it roars off”, he concluded.

John Kingham, managing director of the Treasury’s public services and growth directorate, said the bench marking and market testing of PFI service contracts was at an early stage.

“We absolutely agree that this is a challenge”, he said.

The Treasury kept a close eye on the situation and provided practical support for procurement authorities with standardised contracts, skills training and advice, Kingham added.

But the committee was unimpressed and, at the end, Leigh dismissed the witnesses with some harsh words.

“Given that we are supposed to be in front of the brightest minds in the civil service, we have not found your performance very reassuring,” he said.

And it wasn’t just civil servants who were the subject of Leigh’s ire. PFI was beginning to look like “an enormous wasted opportunity, and the tax payer is paying the price”, he added.