Medical leaders have warned that thousands of NHS doctors are expected to quit within three years after the introduction of a new contract which means they can retire early on full pensions.

By 2007 nearly 4,000 senior consultants will be lacking a financial incentive to continue working for the health service.

Paul Miller, chairman of the British Medical Association’s consultants’ committee, said: "You could find you go into work on April 1, 2007 and every consultant over the age of 60 in the NHS has retired.

"The majority will have hit their best point financially, and will want to go.

"It could be a retirement timebomb. You only need to lose one consultant from a speciality team and it will leave a big hole in provision."