Tories warn of threat to GPs

He said about 1,700 surgeries would shut - one in five - without consultation with residents, and compared the plans to the controversial post office closures programme.

Under ministers' plans, each site would house up to 25 GPs, opening from 8am to 8pm, dispensing drugs, and having facilities for minor operations.

Mr Cameron said he accepts that it is "often a very good thing" to combine services and that the polyclinic policy is not simply a cost-cutting measure.

But, in a speech to a leading health thinktank, he insisted that such mergers should be allowed to happen "naturally" and not be forced on communities.

"The people who need GPs the most are the elderly, those with small children and those with long-term conditions.

"Those are the people least able to get to a polyclinic, and least comfortable in a large impersonal institution. They like to rely on the doctor they know, at the end of their street, often in a building not much bigger than a house.

"They have a human relationship with their GP that they simply won't have with a member of staff at a polyclinic. So I don't object to polyclinics in principle. I object to the principle of imposing them on local communities without public support and against the wishes of GPs themselves.

"Where they occur, they should occur naturally, as the voluntary combination of free agents, not as the latest structural re-organisation of the NHS."

However, Health Secretary Alan Johnson accused Mr Cameron of misleading the public over the plans. He said: "We are opening 150 new GP-run health centres, open from 8am to 8pm, seven days a week. And because this programme is all paid for with new money, none of it will lead to a reduction in traditional GP services."