The Government body in charge of the curriculum in Wales has been accused of introducing an authorised version of history with its decision to commission textbooks.
Professor John Fines, president of the Historical Association, said on Wednesday that he was "gobsmacked".
"The curriculum is something the Government can have some concern in, but not to the degree of providing its own materials."
It was particularly worrying, he said, in the case of history, a subject that depends on interpretation. If teachers relied on these books, "anything could happen," he said.
ACAC (Awdurdod Cwricwlwm Cymru) is investing Pounds 2 million in the production of Welsh language and bilingual materials over the next two years. The publisher Hodder and Stoughton has been commissioned to produce all the history books and authors are chosen, said David Lea, editorial director of Hodder and Stoughton, "in close liaison with ACAC". The first history textbook was published two weeks ago.
The ACAC's English equivalent, the School Curriculum and Assessment Authority, does not produce or commission textbooks. A spokeswoman said: "We don't see it as our job to set up in competition or in parallel with existing authors and publishers. After all, we're using Government money."
John Williams, chief executive of ACAC, said that the books had been commissioned because there was a dearth of bilingual history texts. The gap, he said, was identified by the Welsh Office before ACAC's existence. The project was put out to tender and the Welsh Office decided to give the job to Hodder and Stoughton.
"ACAC has a particular responsibility to produce materials to foster the teaching of subjects through Welsh." He said he trusted teachers' professional judgment not to rely exclusively on these books.
But Professor Fines said: "There is a kind of acceptance culture around. If the book was there, the teacher might well say we'll work on that. I can see that there may not be many materials in Welsh, but if it is possible for government agencies to say what we ought to know about, then the chances of enquiry-based history surviving are slim."
Chris McGovern, a history teacher and former member of SCAA's history panel who has consistently argued for a more traditional approach to history teaching, agreed: "Once teachers realise that the books are coming from the authority, they will be more likely to use them. There's a ring of state control about this."