Armed Police

The police commissioner for Powys has a poll out at the moment - see http://www.bbc.co.uk/news/uk-wales-32422696
Apparently 74 police officers in Dyfed-Powys regularly carry firearms while carrying out their duties.
That's not duties that require a firearms officer - it's normal duties.
Yet this area has a low crime rate, so why on earth is it necessary?

Back in the 1970s, my dad was a police marksman with the Manchester Police. He carried firearms only when he was acting as a police marksman - the rest of the time he carried out normal duties without needing to be armed. He was also a sergeant in the CID. They didn't even have stab vests in those days! Bear in mind that this was at the height of the Troubles, and bombs were going off in Manchester town centre - a far cry from rural Wales today.

So how did we get to a situation where 74 police officers are going out armed all the time?
It would be interesting to find out how often they use their firearms, and under what circumstances.