The Association of Teachers and Lecturers has voted to lobby the government over “excessive” chief executive pay in academy trusts, demanding new rules and guidance for schools.

Delegates at the ATL’s annual conference in Liverpool today overwhelmingly backed a motion on CEO remuneration and called for tighter rules.

It comes after Schools Week’s annual analysis of chief executive pay found a huge disparity in salaries of chief executives and the size of their organisations.

This has to stop. As well as being immoral, it is unsustainable

Simon Clarkson, a teacher from Leicestershire, reminded the conference this morning he had warned two years ago that unions must “guard against the rot of greed in terms of executive headteacher pay”, and said things had “got even worse” since.

“Executive headteachers have morphed into CEOs and the number of obscene salaries paid has increased,” Clarkson said.

“A small number of people have decided to treat education as a gravy train, and are milking schools, taxpayers and the funds that should be there for the children for all their worth. This has to stop. As well as being immoral, it is unsustainable.”

Bob Groome, from Norfolk, claimed the top nine chief executives in his county earned more than £1m between them in 2015, four times the amount paid to the head of children’s services.

“The government say that they are paying more money than ever into education, and now we know where it is going.

“It should go to properly educate our children with good quality, experienced, qualified teachers, instead of unqualified instructors or support staff and not line the pockets of the few who think they have a right to make a buck from our children’s education.”

Tim Jefferson, also from Norfolk, said being a chief executive was a “huge responsibility”, but warned there was a “distinct lack of recognition that this is public money that could be better spent elsewhere”.

The National Governance Association (NGA) has previously lobbied the government to publish benchmark salary figures to help governing boards set CEO pay.

The government has not done so, but said such information was available to trusts on request.

The NGA has urged governors to have “courageous conversations” that sometimes “should involve saying no” in pay discussions.

Lord Nash, the academies minister, also wrote to chairs in October to stress the importance of establishing and monitoring policies for executive salaries so “that you and your trustees would be confident to expose them to public scrutiny”.

But Vicky Browning, from the charity chief executive leader membership body ACEVO, previously told Schools Week that any “insistence on lower pay at any cost” would result in migration to the private sector. “This would leave not only charities, but our communities worse off.”