The decline in NHS productivity that the government has cited as grounds for health reform is “a myth”, it has been claimed.

The suggestion that productivity has declined over the past 10 years is inaccurate, according to Professor Nick Black from the Department of Public Health and Policy at the London School of Hygiene and Tropical Medicine.

In an essay published by The Lancet, Professor Black said data showed productivity had risen, contradicting government claims.

Lancet editor Dr Richard Horton said if the figures undermined the reasons for the controversial Health and Social Care Bill, the changes it would lead to were “entirely unnecessary”.

He added: “This is further evidence to kill this damaging and dangerous bill.”

Professor Black said conclusions that hospital productivity has declined by 1.4 per cent a year, and overall NHS productivity by 0.4 per cent a year, were based on analyses by the Office for National Statistics.

He added the figures were based on estimates of changes in the quantity and quality of NHS care but these may have been underestimated because they were restricted to three aspects of heath care.

He said the major cause of concern was the estimate of quality improvement, which was judged to have risen by 0.8 per cent a year.

However, Professor Black said the improvement was actually considerably greater.

He added deaths in adult critical care had fallen 2.4 per cent a year and deaths after heart attacks improved 5.3 per cent a year and patients’ experience rose steadily.

He said this data suggested quality has improved by considerably more than the assumed 0.8 per cent a year and added it would only take an increase of 1.3 per cent a year to tip the balance from a decline in productivity to an increase.

Professor Black said: “Declining NHS productivity in England between 2000 and 2009 is just one recent myth in health-care policy.

“Many other myths have arisen in the past and many more will do so in the future. We cannot prevent myths developing but we should remain vigilant, spot them as early as possible, and attempt to minimise the harm they can do in distorting understanding and misleading policy makers.”