The harassment of David Miranda beggars belief. But, as Andrew Sullivan says, at least it shows us where Cameron & Co stand.

David was detained for nine hours – the maximum time under the law, to the minute. He therefore falls into the 3 percent of interviewees particularly, one assumes, likely to be linked to terrorist organizations. My obvious question is: what could possibly lead the British security services to suspect David of such ties to terror groups?

I have seen nothing anywhere that could even connect his spouse to such nefarious contacts. Unless Glenn is some kind of super-al-Qaeda mole, he has none to my knowledge and to suspect him of any is so close to unreasonable it qualifies as absurd. The idea that David may fomenting terrorism is even more ludicrous.

And yet they held him for three hours before informing his spouse and another six hours thereafter. I can see no reason for those extra six hours (or for that matter the entire nine hours) than brute psychological intimidation of the press, by attacking their families.

More to the point, although David was released, his entire digital library was confiscated – including his laptop and phone. So any journalist passing through London’s Heathrow has now been warned: do not take any documents with you. Britain is now a police state when it comes to journalists, just like Russia is.

In this respect, I can say this to David Cameron. Thank you for clearing the air on these matters of surveillance. You have now demonstrated beyond any reasonable doubt that these anti-terror provisions are capable of rank abuse. Unless some other facts emerge, there is really no difference in kind between you and Vladimir Putin. You have used police powers granted for anti-terrorism and deployed them to target and intimidate journalists deemed enemies of the state.

You have proven that these laws can be hideously abused.

Not in particular the advice to foreign journalists in transit. Leave your laptops, phones and USB sticks at home.