Industrial action by school leaders will be “necessary” if members reject the “inadequate” pay offer from the Government, a union leader has warned.

The National Association of Head Teachers (NAHT) has said it could move to a second formal industrial action ballot if its members turn down the pay offer.

After a period of intensive talks, the Government has offered teachers a £1,000 one-off payment for the current school year (2022/23) and an average 4.5% rise for staff next year (2023/24).

The National Education Union (NEU), which has staged recent strikes over pay, has urged its members to reject the offer – and one of its leaders has refused to rule out fresh strikes on exam days.

Downing Street said it would be “hugely disappointing” if strikes disrupt exams for pupils in England.

Now the NAHT, which represents school leaders, has said it will ballot its members and ask whether they accept or reject the offer, and whether they will be prepared to vote in favour of industrial action if the offer is rejected.

Paul Whiteman, general secretary of the NAHT, said: “We do not believe that this offer addresses the pay erosion the teaching profession has seen for more than a decade.

“Nor does it address the crushing weight of unreasonable accountability or workload.

“As such, the offer fails to address the recruitment and retention crisis that is damaging the quality of the education for children and young people.

“Furthermore, NAHT’s national executive committee does not believe that sufficient funding is being made available to meet even this inadequate offer.”

He added: “If members reject the offer, it is clear that industrial action by NAHT members will be necessary.”

The NEU, the largest education union in the UK, has said it plans to hold two further days of strike action on April 27 and May 2 if its members decide to reject the pay offer.

On Tuesday, Mary Bousted, joint general secretary of the NEU, said teachers do not want to take industrial action on exam days but refused to rule it out if members agree to turn down the pay offer.

Dr Bousted told BBC Radio 4’s Today programme: “Our executive committee looked carefully at the offer and decided it was really insulting and that the union had to offer advice to members, who will either take that advice or ignore us.”

Asked whether strikes could disrupt exams, she said: “We really hope that that doesn’t take place.

“What we hope is that, if the members do reject the offer, we want to go back to the Government and say ‘You have to do better’, reopen negotiations, and let’s see if we can get an offer that members will find respectable.”

On possible disruption to exams, the Prime Minister’s official spokesman said: “Obviously, that will be hugely disappointing and disruptive for children and for parents.”

He added that he hoped members from the unions would accept this “fair and reasonable deal and step back from strike action”.

Other unions representing teachers and school leaders, including the NASUWT and the Association of School and College Leaders (ASCL), have said they will also ask for feedback from members on the pay offer.

Meanwhile, nurses, ambulance crews, physiotherapists and other non-medical NHS staff are also voting on whether to accept a pay offer made by the Department of Health and Social Care (DHSC).

Health Secretary Steve Barclay described this as a “hugely positive step” after “weeks of constructive talks”.

“This fair and balanced offer recognises the vital role these hardworking NHS staff play, while protecting our commitment to halve inflation – and I urge union members to accept our offer,” he said.

“I’m working with the Treasury to ensure my department has the money it needs to fully fund this pay offer, which will include additional funding and reprioritising existing budgets.

“This is on top of the existing funding we have already made available for a pay increase of up to 3.5% in 2023-24.

“I want to be clear – there will be no impact to frontline services or quality of care as a result of this offer,” he added.

Sir Julian Hartley, chief executive at NHS Providers, which represents NHS trusts, has called for any pay uplift agreed to be funded by new money.

He said: “Reprioritising existing budgets could drain funding from other vital areas of the NHS in the long term, putting frontline NHS services at risk of being cut or severely scaled back.”

Prime Minister Rishi Sunak has declined to set out how much new funding will be made available for pay rises given to end strikes from NHS workers.

Mr Sunak told the Commons Liaison Committee that he “doesn’t want to get in the middle of” negotiations between the Treasury and Department of Health and Social Care.

The British Medical Association (BMA) has said no “credible offer” has been made for junior doctors, who will be staging a 96-hour walkout from April 11.

Civil servants, driving examiners and Passport Office staff will also continue to strike throughout April over pay and conditions.

The Rail, Maritime and Transport (RMT) union has suspended strikes which had been scheduled for March 30 and April 1 to engage in further talks with the Rail Delivery Group.