The owners of some historic properties are refusing to let members of the public visit them, even though they have had grants to repair them from English Heritage.

Although most of those surveyed by the National Audit Office (NAO) were open to the public in accordance with grant conditions, 12 of those contacted refused to let members of the public in - and some even tried to charge �50 for entry.

The NAO says English Heritage should do more to ensure owners comply with its rules.

English Heritage makes grants under the Historic Buildings and Ancient Monuments Act 1953, towards the cost of the repair of buildings of outstanding historical or architectural interest.

10 year minimum

In the last three years it has awarded �24m to town halls, charities, private owners and conservation groups.

Historic properties which get repair grants from the heritage body must agree to open to the public for at least 10 years, and longer if their grants are more than a �100,000.

Some smaller properties are only expected to welcome visitors who make an appointment first.

The scandal was first highlighted last year by TV comedian Mark Thomas, who visited several stately homes to view rooms refurbished at taxpayers' expense and was refused entry.

He said the grant scheme often amounted to little more than a hand-out to house-proud aristocrats.

Mystery shoppers

The NAO says English Heritage could do more to publicise which properties should be open and it says many owners are not obeying the rules.

It asked a firm of consultants to conduct what it calls a mystery shopper survey.

Out of 317 properties contacted it says 42 failed to respond to repeated phone calls over a three week period.

Two said the consultants could only visit if they paid �50. Twelve simply refused access.

Many other owners were friendly and helpful, but the NAO says people who get taxpayers' money should honour the conditions attached to it, and English Heritage should see they do.

Auditor General, Sir John Bourn, said: "Individuals in receipt of taxpayers' money have a public responsibility to honour any conditions attached.

"English Heritage need to do more to monitor compliance. Our work shows that while the vast majority of grant recipients comply with access requirements, a small number do not."