Part of the problem is that signing the petition or not is a matter for the individual. The EDM is another matter.

Many (Labour) MPs - even if asked by their constituents to do so - will be unwilling to be seen to support anything that is critical of the current Government.

I have written to ask mine to sign - but it is mostly unlikly that he will be prepared to sign it. Especially now that he is a junior minister in that Government.