There is a new threat to the Defamation Bill.

No sooner had the proposed law been liberated, after being taken hostage by Leveson negotiations, than Conservative MPs have begun messing with crucial free speech provisions.

Former libel lawyer Sir Edward Garnier MP has tabled an amendment seeking to remove a crucial clause from the Defamation Bill. The clause places some limits on corporations’ use of the libel laws. It does not bar them from suing entirely – just asks that they show financial loss before they do so. It’s an objective and measurable test for companies, who after all do not have feelings.

Such a law would have discouraged the crippling libel cases brought by Big Pharma against Dr Peter Wilmshurst and Dr Ben Goldacre. It would have helped Simon Singh. It would stop the costly ‘lawfare’ waged by the extractive industries around the world against human rights groups like Global Witness. It would stop scientists and doctors from having to decide whether to speak out for their patients and risk selling their house in order to pay legal fees… Or keep their mouths shut.

The clause is an entirely sensible provision that was recommended by the Culture, Media and Sport select committee, and the pre-legislative scrutiny committee, chaired by former Tory Party chairman Lord Mawhinney.

Crucially, it is Liberal Democrat Party policy, and was in the 2010 manifesto that elected 57 Lib Dem MPs.

Libel Reform and the Defamation Bill has been driven by the Liberal Democrats. Lord Anthony Lester and Dr Evan Harris were championing this cause when the other parties ignored the problem. Justice Minister Lord Tom McNally is the coalition lead on the Bill. The Lib Dems were the first to include Libel Reform in their party policy.

And yet, we do not know how coalition MPs will vote on the amendment! Conservative MPs, who are temperamentally friendly to wealthy corporations, are likely to vote with Sir Edward. They may well be whipped by their front bench to oppose any limits on the actions of corporations.

But what of the Liberal Democrats? The Libel Reform Campaign is deeply concerned that the leadership they will go along with their Conservative colleagues in Government, and tell Liberal Democrat MPs to support Sir Edward’s amendment. This would be yet another vote against a manifesto commitment.

The leadership have not said anything in public yet. It is likely they are considering their position now. Labour support the clause, so the Liberal Democrat vote will be crucial.

The Libel Reform Campaign are urging all Lib Dem activists to contact Nick Clegg, and ask him to stand up to the corporate libel bullies and deliver a policy on which the General election campaign was fought. And we hope all readers will contact their MP, asking them to oppose Sir Edward’s attack on the Defamation Bill.

There is a real chance next week to expand the space for free speech in the UK. It is no exaggeration to state that Liberal Democrat activists can make the difference. Please hold your party leadership to their manifesto pledge.

* Robert Sharp is Head of Campaigns & Communications for English PEN.