By Nick Triggle
Health reporter, BBC News
Children under five were expected to get the vaccine from December
Plans to vaccinate healthy children under the age of five against swine flu are in disarray after doctors refused to sign up to a deal.
GPs are already immunising people with health problems and pregnant women.
But the British Medical Association and government have ended talks on children after they failed to agree a deal.
Health visitors and district nurses are now to be asked by local NHS managers to step in - but the programme may not now start in December as planned.
However, the vaccination of the first wave groups, which also include health workers, is continuing as normal as they were covered by a deal that was brokered in early autumn.
It is thought the latest talks broke down over the amount of flexibility the government was willing to give doctors over the rest of their workload.
Negotiators had offered doctors £5.25 per dose - the same as they are getting for the first priority group.
But the BMA had argued doctors should be given leeway over fulfilling their obligations on access to appointments.
Under the terms of their contract, doctors are paid bonuses to give most patients appointments within 48 hours as well as allowing them to book in advance.
Without this, the BMA argued vaccinating 3m children during the busy winter period would leave doctors out of pocket - doctors consider young children to be time-consuming as parents often have to be reassured.
Dr Laurence Buckman, chairman of the BMA's GPs committee, said: "We sincerely wanted to be able to reach a national agreement.
"Unfortunately this has not been possible, because the government would not support adequate measures to help free up staff time.
"At the busiest time of the year for general practice, with surgeries already dealing with the additional work of vaccinating the first wave of at-risk groups, we felt this was vital in order to ensure this next phase could be carried out quickly."
Health Secretary Andy Burnham said the breakdown of talks was "disappointing", but he still hoped to get the vaccination of children going by Christmas.
"We are now getting on with the job and asking local health trusts to put local plans in place so that vaccination of these children can begin seamlessly."
It is still possible that some doctors will agree to vaccinate children if they can reach individual deals with their local health managers.
However, the government has asked health chiefs to focus their attention on other NHS workers.
District nurses routinely carry out vaccinations for housebound patients as part of other immunisation programmes, but it remains to be seen whether they will be able to vaccinate large numbers of children.
Health visitors are also likely to be asked to help, but many of them do not have experience of vaccinating and will need extra training.
The British Medical Association believes it will be "very difficult" to get this all in place this year.
And David Stout, of the Primary Care Trust Network, which represents local health managers, agreed there was still a lot of work to do.
"It is more complicated to get separate agreements in place and will take several weeks.
"We don't know who will want to do this so from that point of view it is untested. I can't see it happening before Christmas."