From this link....
MPS Home > Central Operations Specialist Firearms Command (CO19)
CO19 is the branch name given to the Specialist Firearm Command branch of the Metropolitan Police Service that provides firearms-related support to our unarmed colleagues. The branch is comprised of a small number of officers who are highly trained and motivated in dealing with all aspects of the criminal use of firearms. Operationally, our branch is here to provide armed support to allow the vast majority of policing activities throughout London to be conducted in the traditional manner by unarmed officers.
Explains a lot.
England: Where the police have to call the police when a gun is involved.
Now I know where they got the line "Run away, run away" from in the Monty Python movie.