About 15,500 nurses in Northern Ireland have begun strike action in a dispute over pay and patient safety.
The Royal College of Nursing represents about 9,000 nurses who walked out at 08:00 GMT – the first time the union has taken strike action in its 103-year history.
About 6,500 other nurses, who are members of Unison, walked out earlier.
It follows weeks of industrial action by other healthcare workers over the same issues.
The Royal College of Nursing (RCN) strike is set to last for 12 hours while many Unison health staff members, including nurses and paramedics, are staging a 24-hour strike.
Speaking at the Royal Victoria Hospital in Belfast, RCN member Nuala Murray told BBC News NI: “This was incredibly difficult. I’ve been nursing for 37 years.
“This is so unprecedented for us to have to strike but nurses are so fed up, they’ve just had enough.
“Their patients aren’t safe and they need to do something.”
Many appointments and treatments have been cancelled because of the strike, and a number of minor injury units are closed.
The Health and Social Care Board said all emergency departments would remain open as normal, but would be under significant pressure
Mairead Meenan, a staff nurse at Altnagelvin Hospital in Londonderry, said the “fair pay” issue had brought her to the picket line.
“Everybody wants equal pay and equal rights,” she said, adding that nurses in Northern Ireland felt “undervalued” compared to their counterparts doing the same jobs in Great Britain.
She called on politicians to “start talking” and sort the dispute out.
“You get paid loads and loads of money and you would not last 10 minutes in our job,” said Ms Meenan.
How bad is Northern Ireland’s health crisis?
On so many measures, Northern Ireland lags behind the other UK nations when it comes to NHS performance.
Not only does it has the highest vacancy rates, it also has the worst record in terms of meeting waiting time targets for cancer, A&E and routine operations.
The best indication of this is the figures for the proportion of patients seen in four hours in A&E.
England has just seen its performance sink to a record low of just over 81%. In Northern Ireland it is currently below 66%.
Why? The suspension of a devolved government has certainly not helped – delaying everything from new policy to pay rises.
But modernisation of health care in Northern Ireland was already behind schedule before that happened.
Services are spread too thinly across too many sites, so there is a lot of catching up to do – and the more it is delayed the longer it will take.
Health workers say they want to be paid the same as their counterparts in England, Scotland and Wales.
Unions agreed a 6.5% three-year pay rise for NHS staff – excluding doctors – last year, but it was not implemented in Northern Ireland because parity with the rest of the UK was broken by the devolved government in 2014.
The issue has not been looked at again because Northern Ireland has not had a devolved government since 2017.
Health Secretary Matt Hancock said the solution to the strike was to restore devolved government.
“I want to see it up and running so they can get on and run their health service, the way that we do,” he said.
2,800 unfilled nursing posts
The RCN argues the real value of nurses’ pay here has fallen by 15% over the past eight years.
There are just under 2,800 unfilled nursing posts within the health service in Northern Ireland.
The RCN estimates that a similar level of unfilled posts exists within nursing homes.
The nursing vacancy rate in Northern Ireland is 13%, compared with about 11% in England and 6% in Scotland.
This means that for every eight nurses who should be working in Northern Ireland, one is missing.
Analysis: Services pushed to the limit
By Marie-Louise Connolly, BBC News NI Health Correspondent
These are unprecedented times. For the first time in UK history close to 20,000 health and social care works are on picket lines, including about 15,500 nurses.
With more than 300,000 people in Northern Ireland waiting for an appointment, today’s strike is going to push all services over the limit.
As healthcare workers protest and wave flags calling for pay parity and safer staffing levels, what they are also shouting about is a desire to get devolved government back up and running.
While there is a skeleton staff today, and while many appointments have been cancelled, a shortage of staff has been an issue for many years.
On Tuesday night leaders of the five main political parties in Northern Ireland met the head of the NI Civil Service David Sterling and health permanent secretary Richard Pengelly in a bid to avert the strike action.
Earlier they sent a joint letter to the Northern Ireland secretary which “provides cover” for him to intervene in the absence of devolved government.
The letter to Julian Smith signed by the five party leaders said there was “collective support for the restoration of pay parity”.
Following their meeting with the civil service, the parties wanted to meet the secretary of state but the Northern Ireland Office said health remained a devolved matter.
Mr Sterling rejected the argument that he and his colleagues should restore pay parity on the grounds of public interest.
He added the decision was a choice which should be taken by ministers.
Dr Tony Stevens, chief executive of the Northern Health Trust, told BBC News NI that while the health trusts would be delivering a “much reduced” service, they would be able to deliver services safely.
Speaking from the picket line, community nurse Karen Bowes said the strike was a “very sad day” in her 25-year nursing career.
“We didn’t come to this decision lightly and nurses have a heavy heart undertaking these steps,” the RCN member said.
“Our staffing levels are not safe – patients are not safe on a normal day.”
She added that patients she had spoken in advance of the strike were “very supportive” of the actions and urged politicians to step in and sort out the dispute.
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A spokesperson for Health and Social Care Board (HSCB) said major challenges were expected across all health and social care services on Wednesday.
It also advised that if patients or service users have not been contacted, they should attend their appointment/service as normal.
All emergency departments remain open.
“The priority will be on the treating emergency and life threatening conditions first,” said the spokesperson.
“Patients with less urgent conditions may have to wait for lengthy periods.”
The heads of all of Northern Ireland’s health trusts have stated the current crisis in the service has been “years in the making”.
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