Broadband content providers and internet service providers (ISPs) have written to the Prime Minister urging him to defend the right to free speech on the internet.
In an open letter to David Cameron, organisations including the Internet Service Provider's Association (ISPA) have warned against over-regulation of content published on the web.
Concerns have been raised over the right to open discussion amid ongoing reform of UK libel law, which critics believe fails to reflect the way people communicate online.
Nicholas Lansman, Secretary-General of the ISPA, said ISPs are currently in a position where they may have to decide what bears defamatory meaning, putting the intermediary in a position of judge and jury over content.
He added: "We therefore support the call for an innocent dissemination defence, that ISPs should only be forced to remove defamatory material that has been decreed defamatory by a court or competent authority."
Mr Lansman said libel law should be "brought into the twenty-first century" through the creation of a single publication rule.