Mark Stephens, partner at Finers Stephens Innocent, said that the number of academics and scientists approaching his firm after receiving threats of libel action had risen from none just a few years ago to an average of one a month.
He said: "Sometimes it is two or three cases per month ... and we are just one law firm. There has been an increase in the number of attacks on genuine academic and scientific debate and the plaintiffs are being lured to London because it is the libel capital of the world."
Mr Stephens, who is chair of governors at the University of East London, said the shift had in part been fuelled by lawyers looking to expand the market for libel work beyond their old mainstay of celebrity clients. He also attributed it to the growing number of scientists using the blogosphere to post comments, plus the "no-win, no-fee" structure offered by some legal firms.
He added that for every case that makes it to court, many more are settled privately.
Most academics, he said, do not have the money to fight cases on principle, and 90 per cent of those who launch libel proceedings in England win because the law "so favours the claimant".
He lamented the resulting decline in debate and the effect on academic freedom, warning that there had been a "real upswing" in "people with a degree of hypersensitivity".
"Rather than openly debate, they issue libel proceedings," he said. "You don't get honest debate, which I think leaves society the poorer."
He said the "biggest areas of upswing" included academics suing other academics, and science-based businesses suing researchers.
Jack Straw, the Justice Secretary, has set up a working group to review England's libel laws, with some campaigners pushing for reform before the general election.
Mr Stephens advised academics to "frame comments in more guarded terms" to avoid court, but said they should not shy away from criticism where it is due. He urged particular caution in the blogosphere, where "petty feuds between academics blow up all the time".
Accused huddle together to fight the chill
Academics who have personally felt the "chilling effect" of England's libel laws have called on the academy to support reform of the law.
The scholars are urging their peers to sign a petition organised by the Index on Censorship, authors' association English PEN and the charity Sense About Science.
Among them is Peter Wilmshurst, a consultant cardiologist being sued for libel in England by American firm NMT Medical after he raised doubts about one of its products.
The action was launched after he raised concerns at a scientific meeting in the US about how information was being presented in research for which he was the co-principal investigator.
"Despite vindication of many of my concerns by the publication of a 700-word correction, a four-page data supplement and a new version of the research paper, I'm being sued for libel by the US sponsor of the research," he said.
"English libel laws are being used to prevent scientific debate, the disclosure of serious side-effects of medical treatment and freedom of speech."
Also urging academics to back the campaign are Edzard Ernst, professor of complementary medicine at the University of Exeter, who has faced libel claims from the alternative-medicine lobby; author Simon Singh, who is facing libel action from the British Chiropractic Association; and author and columnist Ben Goldacre, who was sued in 2008 for criticising the promotion of vitamins in South Africa to treat patients with HIV.