Mr Sinnott has advocated unity between teacher unions

Steve Sinnott, general secretary of the National Union of Teachers, called the stand-off "extremely damaging".

But he says the NUT will still not sign a workload reduction agreement with the government.

The union says it would mean classroom assistants being put in charge of whole classes.

'Poor relations'

The disagreement between the government and the biggest teachers' union has seen the education secretary refusing to attend the NUT conference.

The workload agreement, signed by the government and the other major teachers' unions in England last year, promises to give teachers more time for teaching, by reducing administrative tasks.

From September, they will also get 10% of their time devoted to "planning, preparation and assessment", according to the agreement's terms.

The NUT, under Mr Sinnott's predecessor Doug McAvoy, has consistently opposed the policy.

The union says that the deal will depend on classroom assistants taking on tasks that should be reserved only for qualified teacher.

In particular, the union says classroom assistants could on occasions be called upon to take charge of whole classes - an argument that the government rejects.

Addressing his first press conference since being named NUT general secretary on Tuesday, Mr Sinnott said: "In the past, we have had disagreements with governments, while maintaining relations and realising each other's position.

"With this particular government, we have had poor relations."

He added: "I think we can normalise relationships and I hope we can. At the same time, we will continue to uphold union policies."

Taking the schools outside the local authority framework is misguided Steve Sinnott, NUT general secretary

Mr Sinnott said both sides had "lost out" over the stand-off.

The government had missed the NUT's "wisdom, guidance and research", while the union itself, despite having 260,000 members, had lost influence on official policy.

He told the conference, at the NUT's headquarters in central London: "To have a situation in which the government has placed education at the forefront of its agenda and is not talking to the largest teachers' organisation is not something anyone could be proud of.

"It's something the government needs to work with us on."

Mr Sinnott, an advocate of stronger links with the other education unions, said a merger was not likely, at least by "this Christmas".

Meanwhile, he criticised the government for saying this week that it wanted to set up 200 city academies, which are state-funded and free to students - but more independent than mainstream secondary schools.

He said other schools were also in "desperate need" of the millions of pounds extra that academies would receive.

Mr Sinnott added: "At the same time, the idea of destroying a local community of schools is something that we are against. Taking the schools outside the local authority framework is misguided."

He promised to campaign against this and the workload agreement.