Silke sends me a link to this Times Online report about how easy it is for any two deranged activists in London to screw up the business of international relations.
Still, the UK, unlike the "International Community" has the tools to correct its loonier legislation once the damage is noticed. I expect cooler minds will make this go away - something that's almost impossible to do in the sovereign-less world of International Law.
If they don't make it go away, I expect a cell of excitable students from our side to get their act together and halt the travel of Saudis, Iraqis, Pakistanis, Palestinians, Syrians, and anyone else about whom anything can be alleged, to the UK. Keep in mind that the allegations don't need to be proved, they merely need to have some plausible-sounding background. I don't see why, for example, Bill Clinton couldn't be arrested next time he flies thru Heathrow. I've heard that Whitewater thing was never totally cleared. Mostly, mind you, but not totally.