According to David Hart, general secretary of the National Association of Head Teachers, schools are trying to extend teaching time to enable them to deliver a broad and balanced curriculum.
And more are expected to do so now that the literacy and numeracy strategies have bedded down and the two-year relaxation of the curriculum has come to an end.
Mr Hart said: oHundreds of schools have gone down this road because they are worried about keeping up subjects like arts and PE while also carrying out the literacy and numeracy strategies.
oUnless the Government makes sufficient resources available to employ the people we need and reduce the overwhelming bureaucracy, heads and teachers will be working longer than the current unacceptable average of 50 hours a week.i Philip Lott, solicitor for the Association of Teachers and Lecturers, has received a steady trickle of inquiries from members concerned about lunch breaks being whittled away.
He said: oMany schools have contemplated extending the day because they are fearful of inspectors' criticism for not covering all subjects. Proposals for an earlier start, a later finish, or most frequently, a shortened lunch hour, are becoming common.
Nigel de Gruchy, general secretary of the Natinal Association of Schoolmasters Union of Women Teachers, said schools were shortening the lunch period to cut down on discipline problems which often occur in the break.
"Schools want to get lunch over as soon as possible and get children back into class. We don't necessarily oppose it but legislation makes it clear that there should be a 'reasonable break'."
One Bedford school reduced lunchtime by 15 minutes from this term and at Kings Road primary, Manchester, there have been three changes in the school day over the past few years.
Headteacher Monica Gault said: "We have lengthened the school day and shortened lunch for practical reasons and to ensure enough teaching time."
Earlier this year Education Secretary David Blunkett caused an uproar amoung teachers' unions when he proposed extending the school day to 5pm.
No formal plans to contract teachers for more hours have materialised. Instead, there has been a mushrooming of out-of-school activities such as homework and breakfast clubs.
Guidance from the Qualifications and Curriculum Authority,promised for February, on how to organise the school day in primaries has been put on hold while the Department for Education and Employment develops Mr Blunkett's proposals further.
A project is under way called "Learning day" in which "activities in school are being linked with those taking place elsewhere".