The court ruled the industrial action was not covered by the current mandate, with unions needing to hold a ballot every six months to legally hold strikes.

The upcoming walkout was challenged by Health Secretary Steve Barclay, who argued they were unlawful.

Government wins court case to stop day of nurses' strike - politics latest

The Royal College of Nursing (RCN) announced strike action between 8pm on 30 April and 8pm on 2 May over pay and conditions.

But Mr Barclay claimed the final day of the strike was due to fall outside the union's six-month mandate for industrial action, granted in November.

High Court judge Thomas Linden agreed with the submission from the government - with no representatives from the RCN's side present in the courtroom.

Following the legal defeat, the union's leader said members would be reballoted for a new mandate.

Pat Cullen, the general secretary of the RCN, spoke outside the High Court after the ruling.

She said: "They [the government] have won their legal public today. But what this has led to is they have lost nursing, and they've lost the public.

"They've taken the most trusted profession through the courts, by the least trusted people.

"And what a day for nursing. What a day for patients. And what an indictment on this government to do this to the very people that have held this NHS together, not just through the pandemic, but an NHS that has been run into the ground and in crisis, caused by this government."

Read more:
Train strikes: New dates announced by Aslef - including on FA Cup final
Sunak's strikes nightmare is far from over

Mr Barclay said: "I firmly support the right to take industrial action within the law - but the government could not stand by and let plainly unlawful strike action go ahead.

"Both the NHS and my team tried to resolve this without resorting to legal action, but unfortunately, following a request from NHS Employers, we took this step with regret to protect nurses by ensuring they are not asked to take part in an unlawful strike.

"We welcome the decision of the High Court that the Royal College of Nursing's planned strike on 2 May is illegal.

"The government wants to continue working constructively with the Royal College of Nursing, as was the case when we agreed the pay offer that was endorsed by their leadership. We now call on them to do the right thing by patients and agree derogations for their strike action on 30 April and 1 May."

Rishi Sunak's official spokesman said the fact court action was needed was "regrettable".

"Late yesterday, Steve Barclay wrote the RCN, to Pat Cullen again, and asked them to call off their final day of the strike given we were confident that it was not legal, they refused again."

RCN members rejected a deal earlier this month which would have seen them given a one-off payment of 2% of their salary, plus a COVID recovery bonus of 4% for the current financial year and 5% for the year after.

This was despite a recommendation from the union's leaders that the deal be accepted.