Doctors are receiving six-figure windfalls in surgery rent and sale payments, an investigation has found.

The taxpayer-funded “notional rent” scheme allows GPs to buy buildings for their surgeries which they then “rent” back to the Department of Health for more than the mortgage repayments, according to the report.

Surgeries are then sold off when the GP retires and they are allowed to keep the profits from the sale of the building.

James Wharton, a Conservative member of the Commons public accounts committee, accused GPs of “fiddling the system” and said he would ask the National Audit Office to open a “full and comprehensive investigation” into surgery funding.

He said: “People are obviously going to be extremely concerned to see that taxpayers’ money is being used in this way.

“For too long these people have profited too easily at the expense of the taxpayer and the government should look at this system and see whether it can be changed to ensure better value for money.”

The investigation by the Bureau of Investigative Journalism and the Daily Telegraph claims that GPs have boasted that they have made six or even seven figure windfalls from the system.

The cost of premises is currently more than £630m each year. “Notional rent” makes up part of this figure.

This would be an increase of 70 per cent since 2004, when the NHS paid out £370m.

The investigation also holds that 86 per cent of GP premises are either owned by doctors or by private companies and are paid for through the scheme, costing the Department of Health £2.5bn in the past five years.

A Department of Health spokesman said in a statement: “This system incentivises GPs to expand and improve services so that people have proper access to modern facilities.

“It represents the cost to GPs of renting or owning the premises, and is a cost that would met by government direct if GPs did not.”