Unions representing Oxford employees of educational publisher Harcourt pledged to ensure that jobs are protected following its sale for £475m to multinational Pearson.

However, there was relief that Harcourt Education, which employs 660 people at Jordan Hill in Oxford, was not sold to a private equity "asset-stripper".

Harcourt is one of the largest publishers of textbooks for UK schools, but has been hit by a slump in its US sales, with profits down 20 per cent.

The sale by Reed Elsevier also includes US-based Harcourt Assessment.

Anna Wagstaffe, secretary of the Oxford and District branch of the National Union of Journalists, said the NUJ and the other staff union, Amicus, aimed to ensure that jobs and conditions were protected.

Dona Veluti, mother of the chapel (shop steward) at Harcourt Education, said: "The chapel (and staff in general) were relieved that we were not sold to a private equity asset-stripper, so from that point of view we took it as a positive development and we are cautiously optimistic.

"However, we have concerns about possible duplication of work and job losses or redeployment, and at this stage we don't know what is going to happen to staff yet."

Harcourt's books and online learning materials are used by teachers and students in primary and secondary schools, with imprints such as Heinemann, Rigby and Ginn.

Pearson chief executive Marjorie Scardino said: "We have long admired these businesses. They bring new intellectual property, capabilities and skills to Pearson, and will enable us to accelerate our strategy of leading the personalisation of learning."

Reed still owns Kidlington-based Elsevier Science, which produces 15,000-plus publications, including medical journal The Lancet.