By Adam Brimelow Health correspondent, BBC News

GPs and ministers are at loggerheads over extended hours

He hopes to persuade them to back a deal on evening and weekend opening.

The government has said it will impose a settlement if agreement cannot be reached with the doctors' union, the British Medical Association.

The BMA said the real agenda was to privatise services and undermine traditional general practice.

Relations between the government and the BMA have reached a new low.

The BMA has so far refused to sanction the deal, but ministers believe the union no longer speaks for the profession at large.

I think almost every GP in the country accepts that following the contract we are not open as much as we ought to be Michael Dixon NHS Alliance Analysis: Is there a demand? GPs' views

The government wants to see a majority of GP practices offering extended hours and has made an offer that would see an average-sized practice with 6,000 patients open an extra three hours a week.

The BMA says doctors are prepared to work extra hours, but any deal should be flexible and should account for the extra costs of staying open longer.

Otherwise, it has argued, patients who come during the day would see services cut.

In the next few weeks, all GPs will get the chance to vote on the offer.

The government has said that if they reject it, ministers will impose a tougher settlement in England.

Health minister Ben Bradshaw said: "I think it stems on our part from a concern that the current leadership of the BMA don't really speak for the profession at large.

"They've misrepresented the negotiations and they've misrepresented the offer that the government is making."

Its exasperation at the situation has prompted the government to go over the head of the BMA, with Mr Johnson writing a letter to every GP in England.

Investment

In the letter, Mr Johnson insists the proposals "do not in any way reduce the substantial existing investment in these areas, and this sort of care is at the very heart of general practice".

But Laurence Buckman, chairman of the BMA's GPs committee, said: "We think this argument over a few hours either way is really a softening up.

"Patients are being prepared to view their GP as not very good and not very willing and not very flexible, and as a result to look kindly on the government's currently favoured model which is that patients should receive general practice from polyclinics."

The BMA said this could herald the demise of traditional general practice - with its focus on continuity and quality of care.

It has sent out thousands of posters to practices, warning patients that the family doctor service is under threat.

Dr Michael Dixon, from the NHS Alliance, which speaks for primary care professionals, said most GPs were anxious to see the issue resolved.

"This makes us seem as somehow against the NHS, almost against our own patients, and that's not so.

"I think almost every GP in the country accepts that following the contract we are not open as much as we ought to be."

Shadow Health Secretary Andrew Lansley said: "This is classic Labour and yet another admission of government failure to negotiate a contract with which GPs are happy and patients are satisfied."