Backbenchers are seeking to amend the motion setting up the committee on the Damian Green arrest

Yesterday it emerged that the committee the Speaker announced he was setting up to consider the issues surrounding the arrest of Damian Green would not only have a Government majority, but that he would not be able to select its membership either.

The Lib Dems have since announced their intention to boycott the committee.

Now, the Guardian's Andrew Sparrow is reporting that backbench amendments with cross-party support are being tabled for the debate on Harriet Harman's motion to set up the committee, which will take place on Monday.

Here's the intelligence he shares on his blog:

"Bill Cash has tabled an amendment signed by 11 other Tories and Plaid Cymru's Adam Price saying that the committee should be chaired by an opposition MP, that it should not have a Labour majority and that it should report by January 30. Douglas Hogg, another Tory, has tabled a series of amendments with the Liberal Democrat David Heath also calling for the inquiry to wind up by the end of next month, but his proposal would make allowance for the report to be redacted so as to leave out any material prejudicial to the Green investigation.

"The Conservative leadership hasn't revealed its tactics yet. One source told me the situation was changing "by the hour". In theory it's a House of Commons matter, which means that MPs should have a free vote, but of course the Green affair has become highly political. David Cameron wants the committee to report quickly – which is what many MPs thought the Speaker, Michael Martin, was promising when he proposed the idea in his statement on Wednesday – but I get the impression that there is no enthusiasm to go into battle under a banner held aloft by Cash. Further amendments could be tabled. The Tories are also talking to the Lib Dems. Nick Clegg has said he will boycott the committee, but I'm told that threat only applies to the committee as proposed by Harman. If Harman's motion gets defeated, and an alternative committee gets set up with a slightly different remit, then the Lib Dems are expected to take part.

"Labour still has a decent majority and normally Harman would expect to win. But some Labour MPs are opposed to the inquiry being postponed and it must be at least possible that a Commons majority could coalesce behind some alternative proposal. Interestingly, Martin himself is thought to be opposed to Harman's plan. On Wednesday and again on Thursday he kept dropping strong hints about how the government's motion was amendable. Monday's vote could be close."