Teachers are calling for a 35-hour week starting this autumn.

Unions are to start talks with Oxfordshire County Council to negotiate a reduction in their working hours.

They claim many teachers in the county regularly clock up 57-hour weeks as they cope with mountains of paperwork to meet Government requirements.

Oxfordshire also has large class sizes and fewer classroom assistants than other counties, the unions claim.

Members of the National Union of Teachers (NUT) and the Association of Teachers and Lecturers have already voted in favour of pressing for a 35-hour week.

The National Association of Schoolmasters and Union of Women Teachers was expected to back the motion at its conference in Jersey today, said Oxfordshire secretary Geoff Branner.

Mark Forder, Oxfordshire Secretary of the NUT, said talks with the county council would start in May.

Of the 35 hours a week, 22 would be teaching time and the rest would be for lesson preparation and marking. Running after-school clubs and societies would not be included in the 35 hours.

He added: "We are looking to reduce teachers' excessive workloads. Some estimates are that they are working 57 hours a week. Much of the workload is because of the need to present Ofsted inspectors with convincing paperwork. We are asked to track pupils' progress to provide the Government's targets are being met."

Bob Martyn, Oxfordshire secretary of the Association of Teachers and Lecturers said that one way of cutting teachers' workloads would be to reduce class sizes from 30 to 25 pupils.

He added that teachers' workloads had been increasing over the past five years.