Ed Miliband has become the first leader of a major party to call for a public interest defence for libel to be written into the statute books.
The Labour leader came out in favour of stronger free speech protections for writers who make inaccurate claims in good faith following a meeting with leading libel reform campaigners, the comedian Dara O'Briain and the science writer Simon Singh, this week, The Independent can disclose.
There are widespread fears that the Government is failing to implement effective reform of libel laws.
Campaigners want journalists, bloggers, scientists and academics to be protected from legal actions by bullying corporations who use Britain's lax libel laws to suppress legitimate criticism.
After years of concern that Britain's courts were having a chilling effect on free speech, the Government is bringing in a new Defamation Bill.
Currently in its second reading, the Bill will make the judicial system less attractive to libel tourists and will bring in a defence of "responsible publication on a matter of public interest".
But campaigners say the reforms do not go far enough and – in their current state – would be ineffective in protecting scientists, academics and NGOs.
In a statement backing stronger reform, Mr Miliband called on the Government to bring in a public interest defence, which would protect a plaintiff from being sued as long as an inaccurate and potentially defamatory article or statement was in the public interest, made in good faith and corrected promptly.
Describing libel reform as a "once in a generation opportunity to update our defamation laws" he said: "The key to a healthy democracy is the right to free speech. But to defend this we need a modernised defamation law that protects citizens and honest discussion from the stifling threat of legal action.
"I commend the work of the Libel Reform Campaign, who are fighting so hard for the reform of our outdated defamation laws, and it's crucial the Government heeds their concerns.
"There's still time to mould this into a successful Bill – and that includes a new public interest defence – otherwise this opportunity risks being wasted."
The Government has so far stalled on bringing in a public interest defence, although the minister in charge of the legislation has suggested tabling an amendment in the Lords.
Speaking in the House of Lords recently, Lord McNally said: "We are trying to provide legislation that gives genuine protection to the scientific community. If there are improvements that give that protection, we will certainly look at them."