Ambulance workers at union Unison are to stage two fresh strikes in the dispute over pay and staffing, it was announced on Thursday evening.
Members of the union at five England ambulance services - including in London - will walk out on January 11 and 23.
The strike will affect the capital, Yorkshire, the North West, North East and South West and follows action by members of three ambulance unions on Wednesday.
The January strikes will each last for 24 hours from midnight to midnight and involve all ambulance employees, not just the 999 response crews, as was the case on Wednesday.
Unison said the new strikes were a direct result of the government’s “repeated refusal” to negotiate improvements to NHS pay this year.
News of the walkouts came as NHS trust leaders predicted on Thursday that this Christmas could be one of the darkest to date for the health service.
They warned strikes threaten to aggravate an “already deeply challenging situation” faced by the NHS.
Health chiefs are working to mitigate the impact of industrial action alongside having to contend with an “incredibly long list of other serious challenges”, NHS Providers said.
Figures for last week show that one in four ambulance patients in England waited more than an hour to be handed to A&E teams at hospitals, while new data suggests patients in hospital with flu in England has “skyrocketed” and Strep A is driving “near record” demand for NHS 111 services.
As ambulance workers walked out on Wednesday, London Ambulance Service warned ill Londoners were “unlikely to get an ambulance” unless they are at risk of dying, and advised those without a life-threatening condition to make their own way to hospital, while health minister Will Quince urged people to stay safe by avoiding “risky” activities.
Health Secretary Steve Barclay infuriated union leaders on Wednesday by saying they had taken a “conscious decision” to harm people by allowing strikes to go ahead.
But many of the striking services’ employees are likely to be exempted from the January action under emergency cover plans to be drawn up locally by each ambulance employer, working with Unison, said the union.
Unison general secretary Christina McAnea said: “It’s only through talks that this dispute will end. No health workers want to go out on strike again in the new year.
“But accusing NHS staff of making a conscious decision to inflict harm on the public by taking action this week was not the health secretary’s finest hour.
“Neither was it a particularly smart move for Steve Barclay to falsely accuse health unions of failing to deliver a national emergency cover plan. The secretary of state knew full well life and limb cover arrangements were being agreed locally by ambulance managers and unions.
“It’s time Steve Barclay stopped with the insults and fibs and called the unions in for proper talks about improving NHS pay.
“Speeding up next year’s pay review body process won’t solve the current dispute, which is about the pitiful amount the government gave health workers this year.
“The Government must stop using the pay review body as cover for its own inaction. This year’s pay rise simply wasn’t enough to halt the exodus of staff from the NHS.
“The Government should right that wrong with an increase better matching inflation. Only then will vacancy rates reduce, allowing the NHS to get back on track and start delivering safe patient care once more.”
After the festive break, Unison will begin to ask around 13,000 staff in 10 English NHS trusts if they are prepared to take strike action in the spring.
This is because the turnout in the previous strike ballot, the results of which were announced last month, fell just below the threshold required by law.
This includes all the remaining five ambulance services in England – the West Midlands, East Midlands, East of England, South East Coast and South Central. There will also be a re-ballot of staff working for the Welsh Ambulance Service.
Health workers belonging to Unison and employed at Great Ormond Street Hospital, Liverpool Women’s Hospital, London’s Tavistock and Portman NHS Foundation Trust and the North West-based Bridgewater Community Trust are being asked to vote again.
There will also be a re-ballot of Unison members working for the NHS Blood and Transplant service.
