All researchers funded by Britain's biggest biomedical charity, the Wellcome Trust, may be required to make their articles freely available, according to radical changes announced this week.
Until now, the academic sector has assumed that any move towards so-called open-access publishing would be gradual.
But this week the trust became the first major funding body to announce that it wants all research papers to be placed in an open-access archive within six months of publication.
Traditional subscription-based journals still dominate the publishing market, and there are few open-access alternatives.
But the trust has revealed that it is talking to the US National Library of Medicine about establishing a European version of PubMed Central, the American open-access archive for life science research.
The aim is to provide academics with a free electronic library of biomedical research from across the world. They will still be able to publish elsewhere first, but after publication articles will be deposited in the archive.
This may cause conflict with some academic publishers who in the past have acquired the copyright of the research they publish.
But Mark Walport, director of the trust, said: "We are determined to make the results of the research we fund freely available to anyone who wants them."
He said he wanted to make sure that new knowledge about disease and health was disseminated widely. The trust, which spends £400 million a year on science, will cover the additional costs of making results freely available.
This week the trust sent a letter explaining its views to all university vice-chancellors.
A spokesperson for the charity said that discussions with the research community were ongoing and no deadline had been set for opening access.
University librarians, who find their budgets drained by increasingly expensive journals, applauded the trust's decision.
But Geraint Rees, a cognitive neurologist at University College London who is funded by the trust, said that the debate over open access had failed to make an impact on many researchers.
He said: "My university pays for all the journals I want, and in my day-to-day work I don't encounter anything that open access would solve. I strongly support the Zeitgeist of opening access, but I am reluctant to cast academic publishers as evil."
He added: "There is an issue of public access to science, but I am not convinced that if Nature were free, the public would read it."
But Dr Rees said that providing free access to research for scientists working in less privileged laboratories in the developing world was a step forward.
Bob Blackwell, chief executive of Blackwell Publishing, said: "I don't think the Government is going to be too keen on meddling with the publishing market. I don't know whether Wellcome will get support from the Department of Trade and Industry."
Speaking on behalf of the Publishers Association, he said that publishers wanted more people to see their information, but were opposed to the idea of the author paying to publish in a freely accessible journal. "That will lead to lower standards," he said.