In a statement, Mr Barclay confirmed he would take the union to court over the second day of a proposed 48-hour strike – arguing that it falls outside their six-month mandate for industrial action.
Tens of thousands of nurses will walk out across England from 8pm on April 30 after rejecting a pay offer. It will be the first nursing strike which will not include exemptions for cancer and emergency services.
RCN General Secretary and Chief Executive, Pat Cullen, said the move was “wrong and indefensible”.
“The only way to deal with bullies is to stand up to them – including in court.”
She added: “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.”
Ms Cullen said the court’s decision was expected “before the end of the week”, but conceded that the union would have no choice but to cut the strike short if it rules in favour of the Government.
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.
“Despite attempts by my officials to resolve the situation over the weekend, I have been left with no choice but to proceed with legal action.
“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 also protect nurses by ensuring they are not asked to take part in an unlawful strike.”
The move threatens to sour relations between ministers and the RCN just a month after they agreed a pay offer that was recommended to members.
The RCN will seek a fresh mandate for industrial action for June to December, with Ms Cullen warning that strikes could continue until Christmas.
In a letter to Ms Cullen, published on Twitter, Mr Barclay said the proposed strike on May 2 “goes beyond the mandate you secured from your members”.
He said: “NHS Employers and the Department of Health and Social Care are confident, after taking legal advice from leading counsel, that the six-month period in which industrial action can be taken by the RCN expires at midnight on May 1 2023.”