Children may have to spend longer at their desks in order for schools to offer the new national curriculum.
Education Secretary David Blunkett yesterday unveiled proposals for a curriculum which will come into force in September 2000.
Citizenship lessons will be compulsory for secondary pupils from 2002, while primaries will be expected to integrate citizenship with personal, social and health education programmes.
All subjects have been slimmed down to create more time for literacy and numeracy in primary schools and the new citizenship lessons at secondary level.
No subject has lost statutory status although ministers plan to make it easier for students to be exempt from the post-14 curriculum.
Meanwhile, there are to be two new maths programmes for 14 to 16-year-olds which will separate competent mathematicians from disaffected students. Struggling pupils will follow a foundation programme and learn to handle figures in real-life situations.
The Government wants to increase the flexibility of the post-14 timetable and has instructed its curriculum quango, the Qualification and Curriculum Authority, to make schools more aware of existing vocational options.
Mr Blunkett believes more teaching time may be needed to deliver the new curriculum. Guidance on teaching time is to be sent to schools alongside the new curriculum document. He warned that some schools were spending less than the recommended time on teaching. The average English teaching week is 25 hours a week compared with 27 in Scotland.
In his proposals David Blunkett says: "It is clear that practice varies widely between schools on the length of the learning day. The higher the number of taught hours, the richer a curriculum schools can offer.
"Such variation must have an impact on schools' ability to deliver the improvement in standards that is needed.
"We will consider how to promote best practice in this area most efficiently and will come back with proposals in the autumn."
However, teachers' organisations condemned the proposals, saying citizenship lessons would overload the curriculum. Nigel de Gruchy, general secretary of the National Association of Schoolmasters Union of Women Teachers, said: "If the Government wants to add to the national curriculum it must stipulate the subjects to be dropped."
John Bangs, National Union of Teachers head of education, added: "We need to have a meaningful consultation and scrap citizenship lessons, if teachers agree there isn't time for them".
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