The British Medical Association and the Department of Health have negotiated the package in a bid to ease the recruitment crisis currently afflicting primary care.

The new GP retainer scheme will help keep doctors in touch with developments in medicine by working on a part-time basis while they take a career break, so that they can practice again in future years.

At present, many doctors are permanently lost to general practice because they find it very difficult to keep abreast of developments. It costs more than �250,000 to train a GP.

Dr Judy Gilley, joint deputy chairman of BMA's GPs Committee, said: "As news of the improved scheme has spread we have seen a 50% rise in the number of doctors taking part. Last year there were 654 retainees and now we have almost 1,000 in the scheme.

"If only half of those GPs had been lost to the service it would have represented a loss of �125 million in training costs alone.

"With a severe shortage of family doctors in the country we cannot afford to lose a single doctor and this scheme is tremendously important in retaining them."

Supervised education

Retainee doctors can work up to four sessions (three and a half hours per session) a week.

They must undertake 28 hours of education a year including educational supervision by a named supervisor.

Practices employing a retainee doctor receive an allowance to offset some of the cost of employing the retainee and supporting their educational needs. The remainder of the retainee's salary is paid by the practice.

GPs are usually in the scheme for five years, but there can be an additional three years according to individual circumstances. On rare occasions a further two years can be spent in the scheme giving a 10-year maximum, either continuously or intermittently, for a doctor to be part of the scheme.

Doctors who joined the scheme prior to its revision will transfer to the new scheme.