God, I hope this wasn't some nitwit with a laptop in his backpack. If it was, it'll send safety in London back 60 years.
http://www.timesonline.co.uk/article/0,,2087-1697326,00.html
July 17, 2005
Police snipers track al-Qaeda suspects
UNDERCOVER police sniper squads are tracking as many as a dozen Al-Qaeda suspects because security services fear they could be planning more suicide attacks, writes David Leppard.
The covert armed units are under orders to shoot to kill if surveillance suggests that a terror suspect is carrying a bomb and he refuses to surrender if challenged.