The Health Bill will make family doctors’ work “infinitely harder” and threatens to damage their relationships with patients, a GPs’ leader have warned.

In a letter to all GPs in England, the chairman of the British Medical Association’s general practitioners committee Laurence Buckman called on the government to scrap the Bill.

At a meeting this week, the committee agreed that the legislation - currently going through the House of Lords - was “complex, incoherent and not fit for purpose” and would be “irreversibly damaging to the NHS”.

The BMA has already come out in opposition to the bill and called on GPs to write to their MPs outlining their concerns before it returns to the House of Commons later this month.

Dr Buckman said that GPs initially welcomed the plans for clinically-led commissioning, and many have already set up clinical commissioning groups to give their patients more choice over their treatments.

But he warned: “Over time, it has become clear that this is the most top-down reorganisation the NHS has seen since its inception.”

The legislation will create a “new network of bureaucracy” and “the ability for ordinary GPs to change things will diminish”, he said. CCGs’ budgets will be too small for them to function unless they unite into “large and remote units”.

Unless GPs take an active stand, commissioning powers and the day-to-day running of CCGs are likely to be outsourced to private organisations that provide commissioning support services, said Dr Buckman.

“We believe this will lead to the privatisation of commissioning, destroy the public health dimension to commissioning, with a loss of local accountability to local populations, and is likely to exacerbate health inequalities,” he wrote.

The committee has “strong objections” to the Bill’s expansion of competition within the NHS, which it fears could result in fragmented care, the sale of parts of the NHS to private interests and “more chaos at a time when the NHS needs more stability”.

Plans to reward CCGs financially if they commission “well” will create “the potential for damage to the doctor-patient relationship”, as it will leave the impression that they have an incentive to opt for cheap treatments, said Dr Buckman.

And he warned that GPs may be blamed by patients for future closures of NHS facilities, as they will be seen as the ones with their hands on the purse-strings.

Dr Buckman said legislation was not necessary to achieve the reforms that Andrew Lansley is seeking.

He urged the government “to listen and act on the concerns of GPs in the interests of the future of the NHS and what is best for patients - there is a sensible alternative to proceeding with this Bill”.

Responding to Dr Buckman’s letter, health minister Lord Howe said: “Without the bill, we couldn’t remove layers of bureaucracy and reinvest £4.5bn into frontline patient care. And the independent NHS Future Forum found broad support for the principles of handing power to doctors and putting patients at the heart of the health system.”