British scientists should not celebrate victory in their libel reform fight just yet, according to the campaigners who have spent years pushing for change.

A new law on defamation has been passed by the UK parliament, adding protections for peer-reviewed research and provisions to discourage corporations silencing critics with costly libel claims. But there are still concerns, speakers said in their talks at a Libel Reform Campaign meeting in London yesterday. Researchers have been at the forefront of the campaign, after a number of high profile actions against scientists and science writers. (Nature has supported the Libel Reform Campaign: see ‘The right to speak out‘.)

Critically, the meeting was told, there are unanswered questions regarding how the enormous costs of libel actions can be reduced – both to ensure that poorer people cannot be threatened into silence and that they can themselves take action to defend their reputations.

“Only when the costs of defamation actions are brought down … will the law be just,” said Peter Wilmshurst, a cardiologist who has faced legal action, in his presentation.

Another worry is that the Northern Ireland Assembly has not adopted the new Defamation Act. This raises the possibility that libel actions under the old system could still be brought there. Lord Lester, a leading figure in the reform campaign, said that this would scupper the new law.

Lord Lester told the meeting that he would only call for two cheers for free speech as, due to the remaining stumbling blocks, at the moment “I can’t give a third”.