Indeed, apart from what it would do to the number of guns in circulation among criminals is the question of whether the police can be trusted with firearms.
http://en.wikipedia.org/wiki/Police_use_of_firearms_in_the_United_Kingdom#Fatal_incidentsLooking at wikipedia, every fatal shooting by police since 1980 has at the very least a question mark over it if not being downright wrong such as in the case of the brazilian guy de Menezes a few years ago.
I am a serving cop and used to be armed. I know officers who have been involved in shootings (both sides of the weapon) so speak with a bit of experience.
In relation to the stats about police shootings etc. Suspects are arrested at gunpoint pretty much every day and very rarely do these incidents result in a suspect being shot.
Re De Menezes, the environment in which this incident occured was extreme. The fact that someone screwed up is well documented but I think this incident would not have developed in the way that it did if it were not occuring in the aftermath of the London bombings.
More information around the Mark Duggan incident is coming to light every day so I will reserve judgement on that.
Armed response vehicles are a very useful asset but, sometimes can be some minutes away. Those minutes can be a hell of a long time when somone with a gun is nearby!
Would I want to be permanantly armed? No thanks.
Should we as a nation have the debate? I think we should and, if the consensus is yes, then it would become a condition of joining. For those already serving who don't want to be armed, we can leave or be found jobs that don't require arming. After a while, the unarmed officer pool will dissapear through natural wasteage.
That is my 10 pence worth, for what it is worth