A drive to turn patients' right to choose their GP into a reality was launched on Thursday by health ministers, triggering a fresh clash with the British Medical Association, the doctors' trade union.

Ben Bradshaw, the health minister, accused some GPs of operating "gentleman's agreements" not to poach each other's patients, thus effectively eliminating patients' ability to change GPs.

Mr Bradshaw made the accusation as he launched a string of measures intended to promote patient choice and increase competition among family doctors.

They include ending an income guarantee for practices, which can discourage them from taking on new patients; rewarding practices that expand; giving patients more information about the quality of local general practice; and removing a practice's right to operate if it handles complaints badly.

Primary care trusts will also press family doctors to widen the boundaries from which they take patients. In addition, the 150 new surgeries that are to be built - one in each primary care trust - will have much-extended opening hours, and will be allowed to take any patients, not just those registered locally with them.

Mr Bradshaw's charge that some GPs effectively operate a cartel brought an angry reaction from Dr Laurence Buckman, chairman of the BMA's general practice committee. "It is absolute nonsense to suggest that there are gentleman's agreements - it just doesn't happen," he said.

But he warned "nor are we going to compete for patients, that is not the way general practice works".

The government's measures, however, are aimed at promoting exactly that, while also making it easier for primary care trusts to bring in alternative suppliers - including the private sector - where the family doctor service is poor.

The BMA is willing to discuss phasing out the income guarantee, which can see some practices receiving only half as much per new patient as others get for existing ones. It accepts that GPs' pay should better reflect their workload,

The huge annual patient satisfaction survey will be expanded to cover how user-friendly family doctors are; how easy it is to make an appointment, whether telephone consultations are possible, and how courteous reception staff are - with the results published, and pay potentially related to the findings.

More practices should allow patients to book appointments online, Mr Bradshaw said. Patients will be able to register with a practice through the NHS Choices website.

Niall Dickson, chief executive of the King's Fund health think-tank, said patients would not move when services were good and "the vast majority of excellent GPs" would welcome the moves.