'Some Labour MPs suspect the NHS could have run more such centres just as well'

Way back in July when I read the Commons health select committee's report on what we now call independent treatment centres, I was struck by the irritable tone of some of the MPs' conclusions. It gave new meaning to the term 'cross party' and I put the report aside to examine more carefully.

Of course, a lot of complex and sensitive issues are in play when ITCs are discussed, everything from differential pay rates for staff and training to quality of care and foreign doctors, hired in larger-than-average numbers under the 'additionality' rule designed to protect the NHS (at least in the first wave of the ITC programme) from poaching by the dreaded private sector.

But the problem which most got the committee's collective goat was the core one of productivity, which reaches to the heart of the debate about a mixed economy in healthcare provision. Supporters of the historic Bevanite NHS naturally regard ITCs if not as a Trojan horse within the service then at least as a Trojan pony.

It was therefore unfortunate that ministers and officials who gave evidence to Kevin Barron and his colleagues between 9 March and 28 June got into a muddle about the statistics. As you may know, they originally tried to include the nearly 40,000 patients treated by the widely admired BUPA Redwood centre in Surrey in the 60,000 elective treatments done by the ITCs; 250,000 patient episodes if we include diagnostics. Strictly speaking, the Redwood is not part of the ITC first wave, having been set up ahead of it, 'a prototype ITC', as acting NHS chief executive Sir Ian Carruthers nimbly explained when the combative Tory MP Mike Penning rumbled it. Only 60,000 procedures, 35,000 from the BUPA outfit, out of a total of six million done annually by the NHS is not much, he protested to Patricia Hewitt.

'The ITC programme is a small pebble in a very large pool... however, even a small pebble in a very large pool can create a lot of ripples,' the health secretary gamely replied. It did not prevent the report concluding that there had been 'a degree of misrepresentation, witting or unwitting, in some [DoH] public statements' and to voice formal concern at the 'attempt to misrepresent the situation' by using the Redwood figures.

It was not the only such tiff I unearthed when ploughing through the evidence. When Ken Anderson, the department's Texan commercial director, came back for a second roasting (he had 'seemed a little vague on issues' first time round, some MPs had noted) he was asked about pay differentials. Why? Because fears have been voiced that, while ITC consultants' pay seems satisfactory, some lesser staff doing similar jobs side-by-side with NHS staff has slipped.

We're used to that on a sharply sliding scale in journalism, but it's a sensitive topic across the public sector, I realise. Mr Anderson didn't know ('I could get a note back to you'). But it prompted this response from Tory MP David Amess: 'We're wasting our time, chaps.'

Mr Penning: 'If there are people here who know this information, surely we should have it.'

Mr Amess: 'What's the point of this? It is farcical.'

As things turned out, no-one present knew. But you get my drift. Cross-party crossness is not hard to explain. Labour MPs like ex-transport minister Charlotte Atkins and the loyalist GP Howard Stoate suspect that the NHS could have run more such treatment centres just as well and probably for less money.

Though kinder, Dr Richard Taylor, the NHS independent from Wyre Forest, thinks so, too. MPs like Mr Penning fear that ITCs are adding to the crisis in his local (Herts) NHS through ill-judged over-provision. It all makes for a hanging jury.

It is not that the report does not praise ITCs for driving down the spot price of elective surgery, widening choice in some areas or even being a driver of innovation and best practice. What the MPs demanded for a sector scheduled to eventually provide half a million procedures a year is tangible proof of success, not mere anecdote. I have some sympathy for Ms Hewitt's dilemma and her remedies. But the lack of evidence-based policy making has been a curse of the Blair era. We have not heard the last of this row from either side.

Michael White is an assistant editor (politics) ofThe Guardian .