A number of other major health unions, including Unison, the GMB, Unite the Union, and the Royal College of Midwives, have also voted to strike in different parts of the UK, with a series of walkouts planned over Christmas and New Year.

Nurses in England, Wales, and Northern Ireland are to embark on strike on Thursday in the largest action of its kind in NHS history.

Staff will continue to provide “life-preserving” and some urgent care, but there is likely to be a disruption in routine surgery and other planned treatment.

The United Kingdom government said the 19% pay rise demand by the Royal College of Nursing (RCN) was unaffordable, and the RCN said staff had been given no choice after ministers refused to reopen pay talks.

The 12-hour strike will involve nurses in around a quarter of hospitals and community teams in England, all health boards in Northern Ireland, and all but one in Wales, with the exception of Scottish Nurses who will not be striking.

Under trade union laws, the RCN has to ensure that life-preserving care continues during the industrial action. Chemotherapy and kidney dialysis should run as normal, along with intensive and critical care, children’s accident and emergency and hospital neonatal units.

The NHS has said it is “vital” people continue to come for emergency care during the strikes and anyone not contacted to reschedule an appointment should attend as planned.

“Nurses have had enough, we are underpaid and undervalued,” nurse anaesthetist and local RCN steward Lyndsay Thompson from Northern Ireland said, adding: “Yes, this is a pay dispute but it’s also very much about patient safety. The fact we cannot recruit enough nurses means patient safety is being put at risk.”

In England, the first round of strikes will go ahead in 51 of 219 hospitals, mental-health trusts, and community services. The second day of strike will go ahead on 20 December, unless there is a breakthrough in talks.

Most NHS staff in England and Wales have already received a pay rise of roughly £1,400 this year, worth about 4% on average for nurses.

The RCN wants a larger rise, of 5% above the RPI inflation rate, saying its members have received years of below-inflation pay increases, but England’s Health Secretary Steve Barclay said further pay rises would mean taking money away from other front-line services.

Welsh ministers said they were unable to enter pay talks without extra funding from the UK government. Union bosses have offered to suspend strikes if the UK government agrees to reopen serious pay talks.