10,000 ambulance workers across the ambulance services and some NHS trusts have voted to take industrial action over the government's 4% pay award, which the GMB has described as another "massive real-terms pay cut".
It said: "No one in the health service takes strike action lightly – today shows just how desperate they are."
Paramedics, emergency care assistants, call handlers and other staff are set to walk out in nine trusts:
South West Ambulance Service
South East Coast Ambulance Service
North West Ambulance Service
South Central Ambulance Service
North East Ambulance Service
East Midlands Ambulance Service
West Midlands Ambulance Service
Welsh Ambulance Service
Yorkshire Ambulance Service
The industrial action is set to take place before Christmas, with the union planning to meet reps in the coming days to discuss potential dates.
The GMB said workers across the ambulance services and some NHS trusts have voted to strike over the government's 4% pay award, which it described as another "massive real-terms pay cut".
"Ambulance workers – like other NHS workers – are on their knees," said the union's national secretary, Rachel Harrison.
"Demoralised and downtrodden, they've faced 12 years of Conservative cuts to the service and their pay packets, fought on the front line of a global pandemic and now face the worst cost of living crisis in a generation."
The union has assured the public that "patients will always come first" and emergency cover will be available during the walkout.
Health Secretary Steve Barclay said he "deeply" regrets ambulance staff striking and said it is "in nobody's best interests as winter approaches".
But he insisted: "Economic circumstances mean unions demands are not affordable - each additional 1% pay rise for non-medical staff would cost around £700m a year.
"My door is open to discuss with unions ways we can make the NHS a better place to work.
"Our priority is keeping patients safe during any strikes and the NHS has tried and tested plans to minimise disruption and ensure emergency services continue to operate."
What other strikes are due to take place?
The strike comes after the UK's biggest trade union, Unison, announced thousands of its ambulance workers in England also intend to take industrial action before Christmas.
Up to 100,000 nurses from the Royal College of Nursing are also set to stage a mass walkout in December – one of the busiest months for the NHS.
- CWU workers are also planning seven more strikes next month on: 1, 9, 11, 14, 15, 23, 24 December
- Members of the Rail, Maritime and Transport union at Network Rail and 14 train operators are planning four 48-hour strikes on 13-14 December and 16-17 December and 3-4 January and 6-7 January
- Royal College of Nursing has confirmed strikes on 15 December and 20 December
- Ambulance workers, who are part of Unison, are set to strike before Christmas although an exact strike date has not been set yet
- Bus strikes include: Abellio strikes on 1-2 December 9-10 December and 16-17 December and Metroline strikes set for 1-3 December, 8-9 December and 15-16 December
- Around 100,000 civil service members to strike in December and January - dates have not been announced
- More than 100 Eurostar security staff, employed by facilities management company Mitie and members of the RMT union, will walk out on 16, 18, 22 and 23 December
The army has already been placed on stand by in case it is needed to fill the roles of NHS workers while strikes are taking place.
Several strikes are also taking place across other sectors, with Eurostar security staff announcing earlier on Wednesday that they will be taking part in a walkout next month in a dispute over pay.
Members of the Rail, Maritime and Transport union at Network Rail and 14 train operators are striking in December and January as well.