I don't think the Damian Green investigation will result in any prosecution.  However, that does not resolve the issue that he and Chris Galley are being threatened with prison and have already suffered some short period of arrest for something that is part of an MP holding the executive to account.

What surprises me is the extent to which the Labour Government have decided to wade in  behind the arrests.  It does demonstrate a failure to understand that MPs are acting on behalf of their constituents in raising concerns about government failures and that gagging MPs (as this does) has the effect of gagging their constituents.

I don't think it will be a matter for campaigning on the ground, because it is likely that this particular investigation will simply cease without prosecution.  However, the underlying constitutional question still needs resolution.