Media playback is unsupported on your device Media caption NUT's Christine Blower says Mr Gove has a "window of opportunity" for talks

The two biggest teachers' unions are threatening strikes in the autumn in England and Wales over workload, cuts, pensions and plans for local pay.

The NUT and NASUWT announced a wide-ranging joint campaign over what they call the "denigration" of teachers.

The two unions, together representing 85% of teachers, said they would mount an "unprecedented" campaign.

Schools Minister Nick Gibb said that the disruption of strike action in schools "benefits nobody".

The heads of both unions have written to Education Secretary Michael Gove warning of the "deep concerns" of teachers and calling on him to engage in talks with this joint campaign.

They say if the government refuses to "negotiate sensible arrangements" they will "move to escalate industrial action, including jointly coordinated strike action and action short of strike action in the autumn".

'Wild west'

The two unions - now forming their own coalition against Coalition education policies - described their alliance as an "historic joint agreement".

It throws down a gauntlet to government - offering a "time limited" window for talks, followed by the threat of a campaign to oppose education policy.

Occasionally saying we have the best generation of teachers we've ever had in no way compensates for the onslaught of attacks Christine Blower, NUT general secretary

This could include strikes in the autumn term - but the union leaders suggested it could also mean refusing to co-operate with some government initiatives.

At a joint press conference at the British Library in London, NUT leader Christine Blower and NASUWT leader Chris Keates, said the teaching profession was in "crisis".

They set out grievances on a wide range of issues - including pay and pensions - but they focused on their belief that teachers were being subjected to unfair public attacks from government.

Such an undermining of their position made them feel that "there was more stability in the wild west", said Ms Keates.

She said unlike other areas of public service reform, changes in education were characterised by "an almost daily denigration" of professional staff.

Ms Blower also asked what head of a private company would publicly criticise their own staff.

Such pressures were "damaging to teachers' health and well-being", said the joint union declaration.

Local pay deals

This compounded the impact of the increasing cost of teachers' pensions and the "threat to jobs" from spending cuts and the "privatisation" of services, said the teachers' unions.

"Since the government came into office, there has been a relentless and unprecedented assault on teachers' pay and conditions of service," said Ms Keates.

"This assault on teachers is damaging standards of education. Our two unions... are united in our determination to defend education by protecting teachers."

The NUT leader said: "Occasionally saying we have the best generation of teachers we've ever had in no way compensates for the onslaught of attacks and threats to pay, pensions and working conditions."

Earlier this month, the government submitted proposals for teachers' pay that would mean far-reaching changes.

Media playback is unsupported on your device Media caption Schools minister Nick Gibb: "It is surprising... (strike action) benefits nobody"

The submission to the teachers' pay body - the School Teachers' Review Body - suggested that pay could be set at a local rather than national level and would be more strongly linked to performance.

Such plans - which could be in place by autumn 2013 - were criticised by teachers' unions and would be likely to become another area of dispute.

In response to the union declaration, the Schools Minister Nick Gibb said he was "disappointed" and surprised at the announcement - as there were already regular opportunities for teachers' unions to talk to government.

Mr Gibb said that strike action "benefits nobody".

"It doesn't benefit teachers and it certainly doesn't benefit the children who will miss education."

Labour's Shadow Education Minister, Sharon Hodgson, said: "Clearly no-one wants to see schools being disrupted. We urge all sides to continue dialogue so as to avoid industrial action.

"Both sides need to avoid adopting ideological positions, and it's important that the government ceases its dogmatic attacks on the teaching profession."