Obsolete

Are undercover police allowed, or even encouraged, to sleep with "targets" as a means of gaining intelligence on environmental protesters and other political subversives?

One would hope not.  Such a practice would be deeply unethical. It would represent a fundamental violation of trust and an invasion of privacy and cast senior police officers in the role of pimps. The people (mainly women) targeted in this way are human beings, and citizens. It's not just sex on the job, and it's not just "crossing a line": we're talking about the emotional manipulation of people when they're at their most intimate and vulnerable, what one lawyer has described as "the sexual and psychological abuse of campaigners for social justice". It can't be right.
But that's what spies do, though, isn't it? Sleep with sources. Everyone knows that. It works for James Bond. That's what Mr Justice Tugendhat apparently thinks, anyway.

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Here's what he said (at paragraph 177):

James Bond is the most famous fictional example of a member of the intelligence services who used relationships with women to obtain information, or access to persons or property. Since he was writing a light entertainment, Ian Fleming did not dwell on the extent to which his hero used deception, still less upon the psychological harm he might have done to the women concerned. But fictional accounts (and there are others) lend credence to the view that the intelligence and police services have for many years deployed both men and women officers to form personal relationships of an intimate sexual nature (whether or not they were physical relationships) in order to obtain information or access.

In other words, he went on, at the time that RIPA was being passed "everyone in public life would have assumed, rightly or wrongly, that the intelligence services and the police did from time to time deploy officers in this way." So yes, RIPA authorisation probably does extend to sex - provided that the relationships themselves are not "degrading".

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If Bond is a reliable guide on the appropriateness of undercover police officers indulging in sexual relationships with people they are supposed to be investigating for political protest, why wouldn't the officers equally at liberty to liquidate their sources when they cease to be useful? 007 has a licence to kill, after all, and regularly uses it to bump off his conquests. Many members of the public believe that secret agents behave like that anyway, and I don't think Parliament has ever explicitly forbidden it.

Another thing: apart from a short report in the Guardian, today's ruling has had very little media coverage, despite its potentially huge consequences for the rule of law. I realise, of course, that agents of the state engaging in sexual manipulation against peaceful, and essentially law-abiding, protesters matters far less than what some people on Twitter said about what Julie Burchill said in the Observer about what some other people on Twitter said to Suzanne Moore about what she'd written in the New Statesman. You'd think, though, looking at it from the outside (as I do) that the actual fucking police literally fucking duped activists and then using an obscure legal procedure to deny their victims open justice would interest people who call themselves radical and progressive rather more than a throwaway remark made by one self-identified feminist journalist, or even the genuinely offensive comments made by another high-profile feminist journalist a few days later in her defence, which is at the end of the day just words. You'd think so.