The impact of Wednesday's ambulance strike in England and Wales is likely to be worse than that of the one before Christmas, NHS managers are warning.
Thousands of paramedics and support staff will walk out for the second time this winter, in the dispute over pay.
NHS Providers said this strike would be harder to cope with, as the government raised fears over the lack of a national deal on emergency cover.
But union leaders said life-and-limb cover would be provided.
Under trade-union laws life-preserving care must continue.
But there is no formal agreement of what that involves and so it has been left to local services to agree their own arrangements with the unions involved, the GMB and Unison.
Thousands of paramedics and support staff will walk out for the second time this winter, in the dispute over pay.
NHS Providers said this strike would be harder to cope with, as the government raised fears over the lack of a national deal on emergency cover.
But union leaders said life-and-limb cover would be provided.
Under trade-union laws life-preserving care must continue.
But there is no formal agreement of what that involves and so it has been left to local services to agree their own arrangements with the unions involved, the GMB and Unison.