Headteachers have been warned that they could face dismissal or legal action if they refuse to allow staff time off during school hours for marking homework and preparing lessons.

Chris Keates, the general secretary of the National Association of Schoolmasters and Union of Women Teachers (NASUWT), pledged to "out" those head teachers who have done nothing towards implementing the national workforce reform agreement.

Meanwhile, the NASUWT conference heard yesterday that classroom discipline is worsening across the country.

Delegates voted unanimously to expel violent and disruptive pupils permanently from schools.

And at the NUT annual conference, general secretary Steve Sinnott criticised Labour's "romantic fascination" with the private sector.