The government has moved to limit increases in GP pensions, claiming patient services could be at risk if it did not act.
As part of a complex reorganisation under the GP contract, GPs' pension payments could increase by far more than expected.
And health minister Lord Warner warned that other NHS staff could have contributions increased to help fund GP pay-outs if the government did not cap doctors' pensions.
But the British Medical Association believes doctors are being denied pension money they have already paid in contributions.
Lord Warner announced that the 'dynamising factor' for GP pensions will be capped at 48 per cent for money earned from 2003-08. Although GPs are part of the overall NHS pension scheme, their pension is uniquely based on annual income rather than final salary. Contributions are readjusted annually to determine the employer's contribution.
Under the GP contract a much greater proportion of GPs' income is used to calculate pensions, meaning doctors could get larger pensions.
But BMA GP committee chair Dr Hamish Meldrum accused the government of 'reneging on a contract decision', and he called the move 'a betrayal of good faith'.