A leader of the country's biggest teaching union has defended spending hundreds of thousands of pounds on a school funding campaign, saying it will do the same again.
The National Union of Teachers (NUT) spent £300,000 during last year's general election - more than Ukip.
At the union's conference in Brighton on Tuesday, leader Kevin Courtney told delegates the campaign had been a success, winning the support of hundreds of thousands of parents and was responsible for the Government announcing that it would be putting more money into schools.
He urged members to ramp up their efforts ahead of the local elections next month.
Ministers have insisted that more money is going into England's state schools than ever before.
Mr Courtney is now joint general secretary of the National Education Union (NEU) which was formed last autumn in a merger of the NUT and the Association of Teachers and Lecturers (ATL).
He delegates at the NEU (NUT section) conference that their election campaign had a "huge impact", with candidates telling the union that school funding was top of voters' concerns and surveys showing that education was one of the top education issues.
"Conference, our union is proudly politically independent," he said.
"We don't bow down to any Government. We don't tell people who to vote for. But we did tell the truth about school funding and if voters changed their mind because of that - then we are pleased and all politicians should listen.
"You should have no doubt that your campaign was the fundamental reason Justine Greening announced an extra £1.3 billion for schools in the aftermath of the election.
"Some politicians have cried foul. Some don't like head teachers speaking out. Some of them don't like us speaking out.
"Some of them have objected to the NUT spending £300,000 during the Election. Have objected to the fact we spent more than Ukip.
"Well, I say this. We make no apology. We will do it again."
He went on to say: "We now have hundreds of thousands more parental supporters.
"Politicians of all parties should beware. Parents will not forgive education cuts.
"We spent a third of a million pounds and, with that money and your efforts, we won £1.3 million for schools. Nothing like enough. But every pound of it won by our efforts. And every pound means fewer teacher jobs lost, fewer teaching assistant jobs removed, class sizes held just that bit lower and subjects not lost.
"It's not enough. But every pound was a pound that we won for our children's education."
Mr Courtney went on to say that the funding campaign "is not over", arguing "there are still huge cuts facing our schools".
He added: "Parents won't forget or forgive that these cuts are damaging their children's education. A whole generation is affected. Our campaign will ramp up."
Mr Courtney urged delegates to get involved in the funding campaign saying: "Let's make sure that the local elections see candidates being quizzed about their attitude to funding this generation's education properly."