The articles linked to from this post make a claim that the civil servant (one Christopher Galley, apparently) received inducements from Damien Green in return for the information that he provided.
If this is really the case that the police are pursuing, then it changes matters dramatically.
Update: I've just seen that Galley stood as a Conservative candidate in the 2004 local elections (h/t Will)
If Mr Green has been offering inducements to a civil servant for leaks, it is an offence that - when you look at it in more detail - is extremely serious as I've argued over the last few days. It would be a profound debasement of politics and democracy.
If proven, Mr Green would have no option but to resign as an MP and face the full force of the law. And anyone else who knew the score on this would be guilty by implication.
Either way, it's an allegation that requires a detailed investigation and it seems that the police and The Speaker have less of a case to answer.