Professor Nick Black from the Department of Public Health and Policy, London School of Hygiene and Tropical Medicine has branded the declining productivity of the NHS a myth.
Writing in The Lancet on Monday, Professor Black claims the Conservatives, when in opposition, used the 2010 ONS estimates to reject claims by Labour health ministers that productivity was rising to prove that reforms were needed.
He said the myth became a consensus as Labour abandoned its faith in its government policies as it appeared 'exhausted from years in power and bruised by an election defeat'.
The ONS productivity estimates could have been underestimated, according to the professor, because quantity was only based on 80% of activities, predominately leaving out new community services.
Professor Black also claims there is a lack of parliamentary scrutiny as the public accounts committee has to cover all public policies, meaning its members lack expertise. He said: 'Any expectation that the committee might challenge complex economic models underpinning headline conclusions is fanciful'.
Health minister Simon Burns said: 'We have always been clear that productivity in the NHS needs to improve and are committed to better outcomes for patients across the country.
'We are investing an extra £12.5bn in the NHS, but we want to make every penny count. We know the NHS can meet this challenge - we have already made £7bn in efficiency savings over the last 18 months as performance has improved: record low infection rates, mixed sex wards down by over 90% and people waiting over a year reduced by half.
'We are modernising the NHS to put patients first, hand power to doctors and nurses, and reduce bureaucracy by £4.5bn.'