Publishers and learned societies are fighting a last ditch action to stop the research findings of thousands of British academics being made freely available online.

The UK research councils, which control billions of pounds worth of funding, have announced their intention to make free access on the internet a condition of grants in a bid to give British research more impact worldwide as it is taken up and cited by other researchers.

The move has been backed by Sir Tim Berners-Lee, the inventor of the world wide web, and other academics.

But publishers who fear that open access will hit sales and damage the UK's 25% share in the £7bn worldwide learned journals market are lobbying hard against the proposal. Both sides believe the battle has reached a critical stage.

Ian Diamond, the chief executive of Research Councils UK, the umbrella body representing the eight research councils, has proposed that from October academics archive final versions of their papers in repositories belonging to their own universities or subject bodies. These would not be edited, and possibly corrected, by a journal, but would be available free of charge to other researchers via the internet.

This month, the Association of Learned and Professional Society Publishers (ALPSP), whose members publish more than 8,000 journals, wrote privately to Prof Diamond seeking consultation and urging delay.

The policy would not only damage big publishers, but also hurt scores of learned societies, which publish journals, said Sally Morris, the association's chief executive.

Journals organise the all-important peer review process, which is the quality control for research - although the academics involved do it for free - and this has to be paid for somehow, she pointed out.

Once all of a journal's content was available free online, university librarians would stop buying it, she said. The advent of Google Scholar meant it was now easy to find the contents of a journal scattered among different repositories.

Ms Morris conceded that those physics journals where 100% of content was open access had not lost subscriptions yet, but there was a worrying trend of academics no longer reading the journals.

"We are worried that the research councils in the UK are trying to push in the direction of a parallel economy without thinking of the possible damage to the journals on which they parasitise.

"We need to talk together to maximise the dissemination of funded research, but without killing the goose. We need to examine very carefully the real risk to publishers and what we can do to minimise it," added Ms Morris.

But a letter to the research councils signed by Sir Tim Berners-Lee, Stevan Harnad, professor of cognitive science at the University of Southampton, and other advocates of open access, dismisses the publishers' fears.

"Not only are these claims unsubstantiated, but all the evidence to date shows the reverse to be true: not only do journals thrive and co-exist alongside author self-archiving, but they can actually benefit from it - both in terms of more citations and more subscriptions," they said.