The Royal College of GPs has called for the health bill to be scrapped, heaping more pressure on the government's controversial reforms in England.

In doing so, it becomes the first of the medical royal colleges to move to outright opposition.

The college, which represents 34,000 GPs in England, said the overhaul had to be stopped because it threatened to cause "irreparable damage" to care.

It comes after ministers tabled a series of amendments on Wednesday.

The changes included making it clear the health secretary would retain ultimate control over the NHS, and strengthening the requirement of the regulator to ensure the different providers competing for patients also work together to provide seamless services for patients.

They were put forward in response to concerns raised by the House of Lords and will be debated next week.

'No alternative'

But the RCGP said they did not go far enough and it was now time for the whole bill to be withdrawn.

It follows a similar call by the British Medical Association, Royal College of Nursing and Royal College of Midwives

But all three of these are unions, which prompted the government to suggest they were motivated by the dispute over pay and pensions - whereas the RCGP is part of the professional arm of the health service which sets standards.

It is also significant because GPs are widely thought of as one of the main beneficiaries of the reforms, as they are supposed to get more control over how NHS funds are spent.

But the college said they could no longer work with government on the bill because its concerns over competition and bureaucracy had not been addressed.

It also said the overhaul would hamper the ability of the health service to make the savings it has been asked to in the coming years to cope with factors such as the ageing population and rising cost of new drugs.

RCGP chairman Dr Clare Gerada said: "The decision was not taken lightly, but it is clear that the college has been left with no alternative.

"We cannot sit back. Instead, we must once again raise our concerns in the hope that the prime minister will halt this damaging, unnecessary and expensive reorganisation which, in our view, risks leaving the poorest and most vulnerable in society to bear the brunt."

Like many of the medical royal colleges, the RCGP has to date been critical of the plans.

But it had until now been saying it was willing to work with ministers to improve them.

The entire medical royal college community has discussed coming out en masse to oppose the plans, but a draft statement that was drawn up last week was never signed off.

The BBC understands a number of other colleges are currently discussing whether to toughen their opposition.

Health Minister Simon Burns said the move was "disappointing", but not surprising as the college had been critical of the plans.

He added: "We have been carefully listening to the ideas raised as the bill has progressed through Parliament and, as a result, we tabled a series of amendments to safeguard the future of the NHS."