Tory Health Secretary Steve Barclay has confirmed plans to take legal action against striking nurses over next week's walkout.
Nursing leaders accused the Government of trying to "silence members" who are due to down tools from 8pm on Sunday, April 30, to 8pm on Tuesday, May 2, after rejecting the Government's latest pay offer.
NHS bosses have argued that Royal College of Nursing's six month strike mandate in England expires at midnight on May 1.
But the RCN insists there is a legal precedent from a 1995 case relating to a miners' strike that means strike action is lawful until midnight on May 2.
The Government has watered down threats to block the whole 48-hour walkout, instead focusing on the strike on May 2.
In a statement, Mr Barclay said: “Following a request from NHS Employers I am regretfully applying to the High Court to declare the Royal College of Nursing’s planned strike action on 2 May unlawful.
“I firmly support the right to take industrial action within the law – but the government cannot stand by and let a plainly unlawful strike action go ahead nor ignore the request of NHS Employers.
"We must protect nurses [so] they are not asked to take part in an unlawful strike.”
RCN General Secretary Pat Cullen vowed to "stand up" to Government "bullies" in court but said the strike could be called off if the court rules against the union.
In an email to members, she said: “Tonight, the threat sadly became a reality. We told the government that this is wrong and indefensible. The only way to deal with bullies is to stand up to them – including in court.
“Before the end of the week, the court will decide whether to support this government’s use of draconian anti-trade union legislation.
“If the government succeeds in silencing members like you and convinces the court to stop part of our strike, then we’ll have no choice but to cut it short. Our strike action has always been safe and legal. We would never ask our members to do anything unsafe or against your professional code.
“It’s so wrong for the government to use taxpayers' money to drag our profession through the courts. We’re determined to show that the nursing profession is strong and determined and defend our members' right to strike.”
It comes after RCN members voted to reject a 5% pay rise offer from the Government.
