Academic publishers in Oxford fear that textbook sales could decline after a tribunal ruling which means university lecturers can photocopy more material for their students.

Philip Shaw, managing director of Butterworth-Heinemann, in Jordan Hill, north Oxford, and chairman of the Council of Academic and Professional Publishers, said: "This is a very serious development. It potentially puts at risk the market for student textbooks."

Other publishers likely to be affected include Oxford University Press and Blackwell's.

The copyright tribunal ruled that course packs should be included in a new blanket higher education copying licence, which will cost universities £4 per student per year for the next five years. The licence used to cost £3.35.

The universities lost their bid for a reduction in the fee, but the tribunal did agree to scrap the separate fee for course packs, previously about £1m and negotiated each year by the Copyright Licensing Agency, which represents publishers, authors and artists.

Lecturers can copy only five per cent of the total content of a book, but they can now photocopy from different sources without extra charge.

Peter Shepherd, chairman of the Copyright Licensing Agency, said: "The increased royalty fee will certainly be welcome.

"We argued against the inclusion of course packs as part of the fee. We fear there will be an explosion of course pack copying of copyright materials. If so, there is great concern that certain areas of academic publishing will be put at significant risk. This cannot possibly be deemed to benefit education."

The agency said it would monitor the amount of money that authors, artists and publishers received over the coming year.