Nurses across the UK are set to strike in the first ever national action over a pay dispute.
The strike ballot among more than 300,000 members of the Royal College of Nursing (RCN) was the biggest ever in the union's 106-year history.
Although counting is still under way, it is understood that RCN officials believe enough members have voted for winter industrial action which is set to take place within a few weeks, possibly before Christmas.
RCN general secretary Pat Cullen said: "Our strike action will be as much for patients as it is for nurses - we have their support in doing this."
The exact nature of the strike action is yet to be determined, but it will likely see patients face disruption to operations and appointments while already facing record NHS waiting lists.
A union source told the Observer newspaper: "This will see the majority of services taken out, and picket lines across the country."
The RCN said there are record nursing vacancies and in the last year 25,000 nursing staff around the UK left the Nursing and Midwifery Council register.
Recent analysis showed an experienced nurse's salary has fallen by 20% in real terms since 2010, the union said, adding that the goodwill and expertise of nursing staff is being "exploited" by governments across the UK.
The RCN is campaigning for a pay rise of 5% above inflation.
Prime Minister Rishi Sunak and Chancellor Jeremy Hunt already face the huge challenge of tackling a £50bn hole in public finances.
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Mrs Cullen said: "Patients are at great risk when there aren't enough nurses.
"Huge numbers of staff - both experienced and newer recruits - are deciding they cannot see a future in a nursing profession that is not valued nor treated fairly."
She added: "As we begin action, politicians in every part of the UK will be challenged to back their nursing staff and understand the strength of public support."
Cabinet Office Minister Oliver Dowden told Sky News' Sophy Ridge on Sunday programme that the government has contingency plans in place for dealing with any strike by nurses.
"We have well-oiled contingencies in place and the Department of Health is across how we would deal with a scenario like this should it arise," he said.
"We will make sure we prioritise the most essential services - emergency services and so on. But of course there would be an impact as a result of a strike like that.
"I would continue to urge nurses and others to resist to going out on strike even if they have voted to do so. We have already agreed quite considerable support for nurses.
"Of course, if you are in the situation where you have a large number of nurses going out on strike, of course that is going to have an impact for example on some elective surgery and other activities."