In reply to johncoxmysteriously:
whilst the means to gain one from Pakistan in the future clearly exist, apart from the infiltration and normal intelligence gathering giving away their secret, there will be many in their ranks who don't have a death wish, but are very good at recruiting and developing others too. I don't think it would be in their long term goals to use it.
The west obviously has a lot of eyes and ears, either close to or among them. How else could they know a certain boy from England would be in a specific vehicle, on a certain road at a given time.
Dirty bombs, chemical, biological and conventional weapons, pretty much targeted anywhere in the west, I'm sure they would not hesitate. If they did have just the one bomb, they'd probably rather hit Israelis, than Londoners.