Teachers risk becoming “collateral damage” in the political debate around education, heads’ leaders have warned, after Michael Gove delivered the first in what is expected to be many partisan speeches on schools in the run-up to the election next year.

The education secretary set out on Monday a raft of proposals, including longer school days and teacher training to deliver the Classics, that would come into effect under a “Conservative government”.

The speech itself came just days after the Cabinet member sparked a bitter feud with his coalition colleagues after he sacked Labour-supporting Baroness Sally Morgan as chair of Ofsted.

The Liberal Democrat schools minister David Laws was reported to be “furious” over the decision, and led to him making claims that the dismissal was an “attempt to politicise” the schools inspectorate.

Heads and teachers are now concerned that such skirmishes will become a regular feature in the Department for Education over the next 12 months as both parties attempt to distinguish themselves from one another in the eyes of voters.

Russell Hobby, general secretary of heads’ union the NAHT, said he hoped that the political infighting would preoccupy ministers, allowing the profession to get on with their jobs, but admitted it might be wishful thinking.

“That’s the more optimistic view,” he said. “The other is that the workforce will become collateral damage in the debate and that politicians will become more and more extreme in their views about the profession.

“The worry is they will seek to use the profession to drive a further wedge between them and their opponents.”

Mr Hobby added that the amount of infighting within Whitehall had increased in recent weeks.

“If you had asked me six months ago, I would have said [ministers] would have kept their worst troubles behind closed doors, but in the last month or so there has been a rise in conflicts,” he said.

“It’s a bit early for this to start already, usually it’s nine or 12 months before the election, but the worry is that this will carry on and they will start to exaggerate certain issues and make harder and harder arguments.”

Despite these fears, Mr Gove concluded his speech at the London Academy of Excellence by offering a “simple and heartfelt thank you” to the nation’s teachers for “transforming state education”.

But the classroom unions dismissed the comments, stating teachers needed “more than warm words” from the education secretary.

“Michael Gove’s warm words for the profession will mean nothing to teachers who are seeing their pay, pensions and conditions all being cut by him,” Christine Blower, general secretary of the National Union of Teachers, said. “It is time we had an education secretary that did more than play to the gallery. Parents, pupils and teachers deserve better.”