Image caption Websites such as Facebook will be better protected under the bill if their users break libel laws

Plans to tackle internet trolling could have a "chilling effect" on online freedom of expression, a committee of MPs and peers has said.

The Joint Committee on Human Rights warned that libel law reforms might cause website operators to delete statements that had not broken the law.

"There should be a higher threshold put in place before material has to be removed," chairman Hywel Francis said.

The government has accused the committee of over-complicating matters.

Proposals in the Defamation Bill aim to protect website operators such as Facebook or Twitter from claims against them when defamatory statements are published by their users, while making it easier to identify the people accused of making such statements.

'Serious harm'

To be entitled to this protection, the websites must either facilitate contact between the complainant and the author or remove the offending material when they cannot establish contact.

We think there is a real risk that website operators... will too readily make decisions on commercial grounds to remove allegedly defamatory material The Joint Committee on Human Rights

Announcing the plans in June, then Justice Secretary Ken Clarke said the measures would mean an end to "scurrilous rumour and allegation" being posted online without fear of adequate punishment.

Mr Francis, a Labour MP, commented: "We are also glad to see steps taken to protect website operators who are merely hosting content, but, as drafted, the bill could have a chilling effect on those publishing material online."

Under the bill, a statement is regarded as defamatory if it "has caused or is likely to cause serious harm to the reputation" of a person or a company, but any claim for damages will fail if it can be shown, for example, that the defamatory statement is "substantially true".

However, complainants would not have to declare whether any such defence applied in their case.

The committee's report explained: "We think there is a real risk that website operators will be forced to arbitrate on whether something is defamatory or lawful, and will too readily make decisions on commercial grounds to remove allegedly defamatory material rather than engage with the process."

The bill therefore "risks removing material from the internet, which, although it may be defamatory, may be lawful if a relevant defence applies", the report added.

Mr Francis said: "If we are to protect against that threat, there should be a higher threshold put in place before material has to be removed."

Checklist

The committee also called on the government to abandon its "inflexible" approach to another part of the bill, which aims to strengthen legal protections for defamatory statements "on a matter of public interest" that are published "responsibly".

The MPs and peers criticised the government for including a checklist to help the courts determine whether the defence applies, designed to supersede the so-called Reynolds defence.

The committee backed a proposal from Lib Dem peer Lord Lester of Herne Hill, a long-time campaigner for libel law reform, to scrap the checklist and re-write the defence to protect those who "acted honestly and reasonably believed at the time of publication that the making of the statement was in the public interest".

The bill is due to begin detailed scrutiny in the House of Lords on 17 December.

A spokesman for the Ministry of Justice said the government would "give careful consideration" to the committee's recommendations.

"We have already taken steps in areas where the committee has concerns, for example by tabling amendments on the public interest defence in clause 4 of the bill for debate at committee stage in the House of Lords next week," the spokesman added.