The two biggest teachers' unions are threatening co-ordinated strikes in the autumn against Government "attacks" on jobs, pensions, workload and pay.

The National Union of Teachers and the NASUWT announced a "historic agreement", in response to the serious concerns teachers have about the way the Government is "undermining" the education system.

NASUWT General Secretary Chris Keates said: "Since the Government came into office, there has been a relentless and unprecedented assault on teachers' pay and conditions of service."

NUT general secretary Christine Blower said: "We need to stand together to protect our profession and the education system. It is more important than ever that we work together to achieve these goals for all our members."

The unions have written to Education Secretary Michael Gove to seek urgent discussions about the "enormous threats" to teacher morale and the education system itself.

They called on Mr Gove to reach an agreement before the start of the next academic year if industrial action is to be averted.

The two unions represent 85 per cent of teachers in England and Wales.