The Tories have been accused of "scaremongering" over looming ambulance strikes as Rishi Sunak threatened "new tough laws" to prevent disruption.
The Prime Minister slammed the "unreasonable" pay demands of public sector workers and said he would bring forward new legislation to crack down on industrial action at PMQs today.
But Downing Street was unable to give more detail on new plans - as the current legislation only seeks to prevent transport networks grinding to a halt.
The PM's spokesman refused to explicitly rule out banning strikes for ambulance staff but would only say everything was "under review".
Hours earlier, Transport Secretary Mark Harper said legislation was "not a solution" to dealing with the upcoming strikes as it would take time to get through Parliament.
Union leaders blasted the PM for "attempting cheap political shots" instead of getting round the table to solve disputes over pay and working conditions.
The move came after paramedics and ambulance staff from three major unions - Unison, GMB and Unite - said they would take part in coordinated walkouts on December 21, a day after tens of thousands of nurses are due to go on strike.
Health Secretary Steve Barclay is resisting calls to reopen pay talks and today warned that patients would be affected as Government contingency plans couldn't cover everything.
Mr Barclay said there was "a question" whether emergency crews would be able to respond to all urgent calls for category 2 calls, such as strokes and heart attacks.
But Rachel Harrison, GMB National Secretary, told the Mirror: “No one knows yet what cover will be in place on December 21 - least of all Steve Barclay.
“These decisions will be made between workers, their representatives and employers on a trust by trust basis.
“GMB members in the ambulance service save lives every day - they don’t want to put patients at risk and will work with employers to make sure emergency cover is in place.
“Meanwhile this Government’s policies are causing unnecessary deaths in the health service every day.
“Instead of deliberate scaremongering for his own political ends, Mr Barclay should talk to workers about their main concern; pay.”
UNISON head of health Sara Gorton said: "The Health Secretary should be doing everything he can to stop strikes happening in the NHS. That means talking to health unions now about pay, which he’s refused to do so far.
"Ambulance managers will be drawing up cover plans for each service. Unions will discuss those and ensure appropriate responses to emergencies on strike days.
"But instead of speculating about the consequences of a strike, Steve Barclay should be focusing all his energies on stopping action from happening."
The Government is battling to stem a wave of industrial action this winter, with nurses, paramedics, rail staff and civil servants all set for walkouts.
Mr Sunak claimed that the Government had been "reasonable" and added: "If the union leaders continue to be unreasonable, then it is my duty to take action to protect the lives and livelihoods of the British public.
"That's why, Mr Speaker, since I became Prime Minister I have been working for new tough laws to protect people from this disruption."
TUC General Secretary Frances O’Grady said years of Tory cuts have left "public services falling apart at the seams".
“Rather than attempting cheap political pot shots, the government should be getting around the table and negotiating with unions about pay," she said.
"So far, ministers have seemed more interested in sabotaging talks than trying to resolve disputes."
