The head of the UK's nursing union wants to restart negotiations seeking a double-digit pay rise - despite previously recommending a lower offer.

Pat Cullen, the general secretary of the Royal College of Nursing (RCN), had advised members to accept an offer of 5%, but they voted to reject it.

Speaking to Sky News' Sophy Ridge On Sunday programme, cabinet minister Grant Shapps said: "I find this a very curious story indeed because Pat Cullen just recently was encouraging her members to settle for the pay rise that was put on the table.

Image: Nurses on strike outside St Thomas' Hospital in London in April

"It's frankly rather confusing having encouraged her members to accept that deal, she seems to now be coming back and saying the opposite.

But speaking on Sunday, Ms Cullen hit back, saying the decision by nurses to reject the deal in a ballot was them saying "loud and clear" that the offer - of a 9% increase consolidated over two years - was "just not enough".

"They rejected that and they want negotiations re-opened for them and here needs to be more money added to the table," she said.

Asked if a double-digit pay rise was achievable, she said: "There is nothing unrealistic about what nursing staff are asking for.

"The only way that we are going to resolve this dispute is to listen to their voice and make sure this pay dispute is resolved, for patients as much as it is for the profession."

RCN members will be balloted again for strike action on 23 May after the existing six-month mandate ran out at the start of the month.

Ms Cullen described striking as one of the "hardest decisions", and told The Sunday Times that fresh negotiations were needed to prevent six more months of action.

"They [ministers] owe that to nursing staff not to push them to have to do another six months of industrial action right up to Christmas," she said ahead of Sunday's RCN congress in Brighton, telling Health Secretary Steve Barclay talks needed to "start off in double figures".

"It's not right for patients. But whose responsibility is it to resolve it? It is this government."

The nurses' strikes: A timeline

25 November 2022 -The Royal College of Nursing announces it will hold strike action for the first time since its creation more than a century ago in a dispute over pay and working conditions.

15 December - Nurses hold their biggest nationwide strike in history with a 12-hour walkout, leading to thousands of appointments, procedures and surgeries being cancelled.

18 and 19 January - Thousands of nurses hold a further strike over two days

21 January - The head of NHS England warns repeated walkouts by health staff are making workloads 'more challenging'.

2 February - A petition signed by 100,000 people is delivered to Downing Street demanding fair pay for nursing.

6 February - Tens of thousands of nurses and ambulance staff walkout together in the biggest strike in NHS history.

21 February - Nurses agree to pause a major 48-hour strike planned on 1 March for pay talks.

16 March - Unions, including the RCN, suspend further strikes and recommend a new pay offer involving a 5% pay rise for staff this year and a cash sum for last year.

20 March - NHS strikes in Scotland are called off after unions representing midwives and nurses voted to accept the Scottish government's pay offer.

28 March - Up to 280,000 RCN members vote on whether to accept the government's pay offer.

14 April - RCN members reject the deal and announce a 48-hour walkout on 30 April.

16 April - RCN leader Pat Cullen warns nurses could strike until Christmas and calls for the government to improve its pay offer.

21 April - The government takes legal action over the planned bank holiday walkout as the strike mandate runs out during the action on 1 May.

27 April - Strike action planned by the RCN on 2 May is called off after a judge ruled it would be unlawful.

29 April - The RCN agrees to supply some staff during the curtailed strike following patient safety concerns.

30 April - Nurses stage 28-hour strike.

2 May - Most health unions back the new pay deal, although both the RCN and Unite vote against it. The RCN says it will ballot members on further strikes between June and December.

9 May - It is announced nurses will vote between 23 May and 23 June on whether to stage more walkouts.

10 May - Nurses in Wales vote to strike again this summer after rejecting the Welsh government's latest pay offer.

14 May - Ms Cullen calls for Health Secretary Steve Barclay to restart pay talks with a proposed rise in double digits - a move described as "curious and confusing" by cabinet minister Grant Shapps given she had recommended the previous offer to her members.

An RCN spokesperson said: "The negotiations covered two financial years which resulted in a consolidated NHS pay increase of 9%. When our members rejected that, it is clear they expect an offer into double figures."

Fourteen other unions have accepted the government's 5% offer, including Unison, the NHS's biggest union. Others like Unite continue to seek a better offer.

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Earlier this month: Nurse strikes could go 'right up to Christmas'

A health department source added: "It is strange how quickly the RCN leader has changed her tune from recommending this pay deal, which she now refers to as an insult to nurses."

The comments come after Ms Cullen told The Sunday Times: "It's not so long ago since the prime minister went on the media and very publicly said nurses are an exception," she said when asked why nurses warrant a larger increase than other healthcare workers.

"I would totally agree with him... they should be made an exception because they are exceptional people."

The mental health nurse, 58, from Co Tyrone, said patient safety was "at the centre of everything that we do".

"We will do nothing that will add further risk to the patients that we look after," she said, saying increased pay would see nurses return to the profession and ease a staffing crisis.

"The truth is that patient safety cannot be guaranteed on any day of the week. How could you guarantee patient safety when you have 47,000 nurses from your workforce every single day and night?"

"Looking back on this pay offer, I may personally have underestimated the members and their sheer determination," she said.

"I think what I would be saying to the prime minister, Rishi Sunak, is 'Don't - don't make that same mistake, don't underestimate them'.

"Nurses believe it's their duty and their responsibility because this government is not listening to them on how to bring it [the NHS] back from the brink and the message to the prime minister is that they are absolutely not going to blink first in these negotiations."