Anyone who is interested in civil and political liberties will be appalled by the police's treatment of Damian Green.
But the case points to a basic, unresolved contradiction in the way that the British polity handles the task of holding the executive to account. Both Green and the police are caught up in this contradiction (not to mention any civil servant who may or may not have been leaking stuff to Green). The lesson is that, rather than just criticising the police, we need to end this contradiction.
The contradiction is as follows: on the one hand we say, with a nod and a wink, that it is fair game for MPs to use leaked information as part of the process of Parliament holding the executive to account. It is because most of us think this that we see the police action against Green, even if he has been receiving leaked information, as not merely heavy-handed but as undemocratic. On the other hand, in saying this we are also saying, with that nod and a wink, that it is a normal part of the political process that opposition and criticism of the executive will rely on leaks - in other words, on some people, such as civil servants, doing what they shouldn't be doing. So we end up saying, in effect: 'Its fair play to break the rules!'
But it isn't fair play to those who have to break the rules if they are then punished for doing so - for doing what we, as citizens, implicitly rely on them doing to make opposition and criticism of the executive effective. Nor is it fair to say to those who have the job of enforcing the rules: 'Oh, don't enforce them too much.' Under the rule of law, the police's job is to apply the law - and not to pay attention to the nods and winks of the political elite.
As so often in our polity, the problem lies in the excessive power of the central state executive. If it had less power to limit the flow of information we could conceivably have a system in which Parliament could do its job of holding the executive to account without some people breaking any rules. Cases like this indicate how the 'freedom of information' agenda apparently remains seriously unfinished business.