Every GCSE history course will have to include at least 25 per cent British history from September 2001 under proposals put forward by ministers' curriculum advisers.
Leading historians oppose the change and warn it will cause upheaval in schools and restrict pupils' range of study. But traditionalists, who issued a manifesto last summer, gave it a cautious welcome - but only if it results in a compulsory core of British "landmarks and personalities".
Ben Walsh, chair of the Historical Association's secondary committee, said: "We are utterly dismayed by this proposal. We oppose it both as a point of principle and because it will bring problems for schools - in terms of new books and reorganisation.
"Nobody in the mainstream history community has asked for this or believes that it is a good idea."
Chris Culpin, director of the Schools History Project and chief examiner for exam board Edexcel, said: "There is no way that publishers ca get books out in time for September 2001. There may also be problems of teacher expertise."
But Chris McGovern, director of the History Curriculum Association, , said:
"Any move to consolidate the position of British history is to be welcomed.
"But we need to see the details; it will be no improvement if it just means more study of social deprivation, race relations and gender issues. We want a compulsory core of British political history."
All GCSE syllabuses are being reviewed for September 2001 to bring them into line with the new national curriculum.
The GCSE revamp follows the overhaul of A-levels which made it impossible for history candidates to avoid the study of British history from last September.
The new GCSE specifications are being drafted by the exam boards to fit the new criteria. They are due to be submitted to the Qualifications and Curriculum Authority by June and to be sent to schools in October.
A QCA spokesman said: "The revised specifications will not be taught until September 2001. Schools will have plenty of time to adapt."