Official NHS waiting list figures are no more believable than Enron's accounting, says the shadow health secretary.

Comparing the disgraced corporation's financial figures to the government's health statistics, Liam Fox has slated Labour's efforts to reform the health service.

"The NHS is being crippled by a combination of ministerial interference and political incompetence," he said.

"Ministers talk about giving clinicians freedom, but constantly manipulate the NHS to try to meet their targets."

Responding to a highly critical Commons report on waiting-list targets, Fox accused the health secretary of cooking the books.

"You can no more believe Alan Milburn's figures than you can Enron's," he said.

"The public accounts committee is the latest objective organisation to confirm what I have been pointing out for years - that when Alan Milburn fiddles the statistics, patients suffer."

MPs on the select committee claim deliberate manipulation of waiting lists and distorted clinical priorities have undermined public confidence in the NHS.

The 45th and 46th reports of the Commons public accounts committee - published on Wednesday - revealed that at least 10 hospitals had manipulated waiting list data and statistics "to hide the fact that they were missing government targets".

"In some cases the actions will have prolonged the suffering of patients during which their condition may have worsened,'' the MPs said.

And the select committee warned that political pressure was leading to clinical distortions.

"The pressure to reduce waiting lists has led a significant number of consultants to treat some patients before others with higher clinical priority," said the PAC.

"The challenging targets to reduce waiting times can only increase this pressure."

After the issuing of new Department of Health guidelines the situation has improved, note the MPs.

"But there remains some uncertainty about the accuracy of the figures, partly because not all hospitals validate their waiting lists often enough," the committee cautions.Committee chairman Edward Leigh urged ministers to ensure that targets did "not lead the NHS to fiddle the figures or distort clinical priorities".

"The evidence of huge regional variations in waiting times, of distorted clinical priorities and of cases where the waiting lists have been deliberately manipulated undermines public confidence in the NHS," he said.

Fox links problems with waiting list targets to a political failure to reform the NHS.

"Labour appears to have learned the language of reform from the Conservatives. But a combination of ideological obstinacy and stupidity prevents them from applying it," he said.

"Only the Conservatives will carry out the far-reaching reform needed to transform the NHS."

The NHS Confederation has insisted that cases are restricted to a "very small minority" of NHS trusts.

"Doctors and managers need to work together to ensure that patients with the most urgent cases are treated first. We're saddened that in some instances this appears not to have happened," said chief executive, Gill Morgan.

"It is important that the hard work and real progress being made by managers up and down the country to improve patient care isn't obscured by the actions of this very small minority."