Local authorities have warned they will 'resist' health secretary Alan Milburn's plans to give the NHS the power to run social services.
Mr Milburn pushed ahead with the proposals last week, telling delegates to the NHS Confederation's annual conference that the health service national plan would create a new level of primary care trusts with the power to deliver 'integrated care'.
Community mental health services and mental health social work could be delivered through 'a single provider trust', as could care for elderly people.
Mr Milburn said later: 'We have got to stop thinking about social services and health services and we have to start thinking about a care service.'
The plans were 'not one-way traffic', he added. It was 'perfectly possible' for both childcare and child protection to be run by local authorities.
Mr Milburn also unveiled plans to give the NHS more freedom from political control.
Under a 'traffic light' system for rating trusts, health authorities and primary care groups, successful bodies would be given more money and left to run their own affairs while failing organisations would get help and advice. The health secretary also wants to 'depoliticise' decisions on controversial hospital closures, handing power to an independent panel of managers, doctors and nurses, and the public.
But his plans to bring health and social care together sparked opposition from both NHS and local authority representatives.
Jenni Bremner, health policy officer for the Local Government Association, said: 'We do not believe that forced organisational change is in the best interests of users.'
While her members supported designing services around users, they would 'resist' structural change as 'it does not deliver better services for people'.
Ms Bremner said health and local authorities already had the power to pool budgets and work in partnership.
Last month the LGA reacted angrily to similar proposals from the NHS Confederation for health organisations to take over responsibilities from local authorities.
Social workers warned that PCTs - established only in April - were too inexperienced to start working outside the NHS.
Jo Williams, president of the Association of Directors of Social Services, said: 'We should see them prove themselves before we move to super trusts .'
Community trust chief executives warned that the plans would cause 'outrage' among social services chiefs.
One - who asked not to be named for fear of offending her local director of social services - said: 'It makes eminently good sense, but if social services take their bat and ball home it won't work'.
Dr Peter Smith, chair of the National Association of Primary Care, welcomed the plans: 'Anything that actually gets social care and healthcare working together is a good thing because the point at which people lose out is when they drop through the gaps.'
But he warned that it could lead to health service commissioners moving services to local authorities, which have the power to charge users, 'to bring more money in'.
Fees were 'a huge barrier'. Allowing health organisations to charge for care 'would fundamentally alter one of the basic principles of the NHS'.
Ms Williams said social services raised£2bn a year in charges paid by users, but if services moved to the NHS and were provided free, this could 'lead to a gap in the budget'.