> I thought the London police were supposed to be adept in
> the use of truncheons, effective at stunning. Very few
> London police carried guns in the past.
I'm not sure how long it's been since you've been to London, but "plenty" of the various groups charged with law enforcement in the London area carry firearms (they are called "AFO" -- Authorised Firearms Officers -- and at last count, there are ~3,000 of them) ... and in particular, the ones who got this guy were plainclothes, and likely from one of Metro Police's special ops groups.
/jordan