Talks to discuss the Government’s plans to cut teachers’ workloads have degenerated into a public row between the largest classroom union and schools minister David Miliband.

The row centres on the proposal to give teachers guaranteed time for planning, preparation and assessment and to allow teaching assistants to take classes.

The Government has suggested that 10 per cent of teaching time should be earmarked for preparation, equivalent to half a day per week. In a letter published in this week’s TES, Mr Miliband rebuts the contention of the National Union of Teachers that this extra time for planning will be found by extending the school day.

Mr Miliband says that the time will come from within the current contractual 32.5 hours per week and has told the NUT that there is no question of requiring preparation time to be at the end of the school day.

His intervention follows a full-page advertisement in The TES from the union attacking the Government’s proposals, a tactic repeated this week.

The NUT argues that because the Government has refused to say that teachers’ time in the classroom should be cut, preparation time will simply be added to the school day.

Ministers’ offer of guaranteed time for marking and preparation could still lead to a cut in the hours teachers spend with pupils, the Government insisted this week.

A spokesperson for the Department for Education and Skills told The TES that the issue was still “under discussion” and refused to rule out a cut in teaching time.

Talks between the Government and the unions representing teaching and support staff have reached an impasse, with the NUT refusing to accept teaching assistants taking classes and the Government refusing to back down. The two other big classroom unions are more receptive to the proposal.

There is better news for ministers from the talks between school employers and representatives of teaching assistants.

An interim agreement on employment rights, including the controversial issued of term-time and temporary contracts, is expected in January.

Unions have campaigned to secure pay for their members during the school holidays. Earlier this year, a TESUNISON survey found that four in 10 teaching assistants are not paid during all holidays, a practice that can cost staff up to nine weeks’ pay per year.

Agreement on a new career structure for assistants is not expected until March.

Letters, 25, advert, 27

Pull-out Learning Support supplement inside The TES