More than 300 practices -- almost one-third of the total -- have said they will not take part in the Scottish Government’s ­programme, which gives doctors extra money in exchange for extending their opening hours.

Participation rates vary significantly around the country. In Dumfries and Gallo­way, 94% of surgeries have agreed to offer extra appointments outside typical working hours, compared to 44% in the Borders and 49% in Fife. In Glasgow, 69% are taking part and in the Lothians 64%.

Health Secretary Nicola Sturgeon said thousands of patients were benefiting from extended opening hours and called on health boards to urge more doctors to participate.

However, the British Medical Association Scotland said the Scottish Government should review the policy to ensure it was not a waste of taxpayers’ money.

Dr Dean Marshall, chairman of the BMA’s Scottish General Practitioners Committee, said: “We’ve found that the experiences of GPs working in extended hours are mixed. It often depends where the surgery is located and if the NHS board has allowed for some flexibility in the agreement.

“In some areas, GPs have real security concerns, for themselves and their patients, about being in their surgeries alone late at night. Other GPs report that the Government’s refusal to allow them to prioritise working patients for these appointments means they are not taken up or are used by patients who could be seen during normal surgery hours.

“There remains little evidence that extended hours are improving outcomes for patients or if they are being used by patients who would otherwise find it difficult to access GP services during traditional ­opening hours.

“The Scottish Government should review this to ensure that taxpayers’ money is not being wasted on a policy which does not make best use of valuable NHS resources.”

Ms Sturgeon wrote to GPs at the beginning of 2008, asking practices to offer an extra 30 minutes of appointments a week for every 1000 patients on their list, equating to three hours for a typical surgery. In return, she promised extra funding to the tune of £19,000 for the average practice.

However, the BMA has always questioned the wisdom of extending opening hours and says doctors who do it receive about £2.95 per patient, less than they would have to spend to ensure the additional service was appropriately staffed.

Figures from November show 674 surgeries out of the 1017 in Scotland have signed up to extend opening hours. A further eight have indicated they will join and 26 are undecided. A total of 309 have said they will not participate.

Research by the Confederation of British Industry indicates that, across the UK, businesses lose about 38 million working hours and £1 billion each year because employees have to take time off to visit their doctor during working hours.

David Lonsdale, assistant director for CBI Scotland, said: “The fact that far greater numbers of GPs across Scotland now offer a more flexible and convenient approach to opening hours is to be applauded, with the response from GP practices in places such as Dumfries and Galloway and the Forth Valley particularly commendable.”