The NUT teaching union has voted to call a one-day regional strike in the summer term, over school funding cuts.

At the union’s annual conference in Cardiff, delegates today voted to “identify regions” where “strike action could be called using the existing funding ballot and to call a one-day strike in those regions before the end of the 2016-17 academic year”.

Last June, the union voted for strike action to “persuade the secretary of state for education… to increase presently inadequate funding levels”.

This means the NUT is legally able to take industrial action in relation to funding until 31 August 2017. On 1 September, it will merge with the ATL to create a new organisation - the National Education Union - so its current ballot will expire at that point.

Kevin Courtney, the NUT’s general secretary, said the union would consult its members across the country and - in those regions where “teachers are particularly angry” - it would consider “whether we could coordinate action in those regions in summer term”.

He said the thing most likely to “stimulate a one-day strike” would be if the government announces that more money will be taken from certain regions in its response to its consultation on the national funding formula.

James Kerr, the delegate from Lewisham who had called for the action, said the NUT’s strike ballot ended at the end of this term, so the union had to “use it before we lose it”.

While the vote was for a one-day strike, Mr Kerr said the union should be prepared for further action.

“This has to be not the ending but the start,” he said. “We can’t rely on wishful thinking, we cannot rely on an isolated one-day strike, then go back to business as usual.”

Cleo Lewis, also from Lewisham, said: “We have been passive for too long. The government knows that we have been passive, the government have taken advantage of that, and I’ve had enough.

“Nothing gets changed by sitting and discussing… at the end of the day the government are not accepting our nice words we need to show them that we are serious.”

After the vote, the conference heard from Jo Yurky, who co-founded Fair Funding For All Schools - a parent-led campaign against the funding cuts.

Ms Yurky said she was aware of a school in Haringey which children were “taught for the first two weeks of January with their coats and hats on” because the school “had to become a bit more careful about when they’ll turn the heating on - to save money”.