@Mad Mike: "...I'm really surprised they don't already have this."
Who says they don't? Isn't it possible (if not plausible) that they do already have this, and this "leak" is their way to gauge the public's reaction?
@Conrad Longmore: "So, we know the bad guys are coming. It would be irresponsible for the security services not to step up measures for the duration of the games. And yes, that's going to be a PITA for people living in London and the South-East. Unfortunately, it is something people are going to have to live with.. temporarily.. if they want to be safe."
I'm sorry, but how do you KNOW "the bad guys are coming"? Oh, you mean you ASSUME they are because your fear tells you so? In reality, you can only go so far as to say it's possible, or perhaps likely, that "the bad guys are coming". You cannot say that you know because you don't. Regardless, it's exactly the type of attitude you expressed which erodes our civil liberties in the name of security. Basically, it boils down to three things: 1) citizens that don't give a damn and wouldn't try to stop an attack even if they knew about it; 2) citizens that don't care about living in a fascist society or dictatorship as long as they have a sense of security (whether such security is real or only perceived), and will allow the government to do literally anything in order to achieve that sense of security; and 3) a government that seeks only power and control, a government that does not want to govern its citizens, but wants to rule them.
Also, no offense, but you're a complete idiot if you think such measures will only be "temporary". They will be temporary in the same way that vague laws are never used in ways the authors didn't intend (and/or in ways the authors promised they wouldn't be used).