The Association of School and College Leaders (ASCL) is due to hold a formal ballot for national strike action in England for the first time in its history.
The ASCL said the school funding crisis, the erosion of teacher and leader pay and conditions, and staff shortages were the main factors behind the decision.
The Prime Minister’s official spokesman said Rishi Sunak is “concerned about the overall impact of strike action on children’s education”, but does not want to “pre-empt what their members may choose to do”.
Government attempts to resolve the dispute in March were described by the union as “completely inadequate” – adding that a pay offer was rejected by 87% of the eligible members who voted.
Geoff Barton, general secretary of the ASCL, said: “ASCL has never before formally balloted at a national level and this is clearly a very significant step.
“The fact that we have reached this point reflects the desperate situation regarding inadequate funding, long-term pay erosion, teacher shortages, and the intransigence of a Government which we can only conclude does not value the education workforce or recognise the severe pressures facing the sector.
“This action is taken as a last resort and with a heavy heart, but we cannot accept the continued damage to education caused by Government neglect and complacency.”
The ASCL represents more than 23,000 leaders of primary, secondary and post-16 education from across the UK – including roles such as headteachers and multi-academy trust chief executives.
In a statement confirming the ballot, the union said an executive committee of senior elected members met on Wednesday afternoon and voted unanimously in favour of the vote.
The organisation added that the ballot will be held at a date to be fixed in the summer term, with any resulting strike action expected to take place during the autumn term.
Mr Barton said: “We have made every effort to resolve this matter through negotiations prior to reaching this point.
“Unfortunately, the Government’s offer has failed to sufficiently address pay and conditions and, critically, did not provide enough funding for even the meagre proposal it put forward.
“Following the rejection of the offer by all education unions involved – ASCL, NAHT, NEU and NASUWT – the Government has made no effort to reopen negotiations and has said only that the issue of pay will now revert to the School Teachers’ Review Body.”
Schools in England face five days of teacher walkouts in the summer term and possible action in the autumn as the National Education Union (NEU) is also set to re-ballot members in the ongoing dispute over pay.
Earlier in April, delegates at the NEU’s annual conference on April 4 voted in support of a three-day strike in late June/early July.
The teaching union announced two further strike days on April 27 and May 2 after 98% of its members, who responded in a consultative ballot, voted to turn down the Government’s pay offer.
After a period of intensive talks with unions, the Government offered teachers a £1,000 one-off payment for the current school year (2022/23) and an average 4.5% pay rise for staff next year (2023/24).
The National Association of Head Teachers (NAHT) could also hold a formal ballot on potential strikes after nearly four in five (78%) members said they would be prepared to vote for industrial action.
A Department for Education spokesperson said: “We have made a fair and reasonable teacher pay offer to the unions, which recognises teachers’ hard work and commitment.
“Next year, school funding will be at its highest level in history – per pupil, in real terms.
“We know schools are facing increased costs like energy and staffing, and are providing an extra £2 billion in each of the next two years to cover those costs. As a result, school funding is set to rise faster than forecast inflation in both 2023/24 and 2024/25.”