The report by centre-right Policy Exchange suggests that the current set-up that sees PCTs deciding what clinical services to buy and where from is a 'weak point' for the NHS, and suggests that since GPs operate on a small business model there is an 'inbuilt incentive' for them to have greater regard for the financial implications of clinical decisions.

'All the experts we consulted agreed that whichever political party wins the next general election, the role of commissioning will be key, since commissioning is essentially control of NHS finances,' the report says.

It adds: 'Under a system of fundholding GPs would act with a dual role, simultaneously acting as clinical expert on behalf of the patient and a rationing expert on behalf of the taxpayer.'

Henry Featherstone, head of Policy Exchange's health and social care unit, said: 'Like all public sector spending bodies, the NHS is going to face an increasingly challenging financial environment.

'Beyond 2012, real term increases in funding are likely to be much smaller than the NHS has been used to. In order to meet these challenges, it is going to be far more politically palatable to look at the options for reducing costs, rather than fundamentally altering the principles of the NHS and replying on top-ups or co-payments.'