Terrorist attack Westminster, page-122

Yes, agreed, but on your question, most definitely. NZ Police constantly lose them, see below:
http://www.stuff.co.nz/national/90053775/police-have-lost-guns-and-accidentally-tasered-each-other
Well, they do allow lose them constantly in the States. Noone from internal affairs to the overwatch squad can prove the NRA claims of course but the Police Services do lose them. Victorian Police were not too good at retaining them as Underbelly points out. Four Corners on Australia's ABC made constant references to NSW Police Gun losses. The program "Moonlight State" and Chris Master's program on 4Corners called "The Big League", impossible to see due to injunction proceedings, also referenced gun losses and criminal activity.

If Canadian, NZ, US, Australian and other police forces did not have guns, they could not lose them to those criminals and others who may want to use them, so u would minimise the risk of them in the wrong hands like in England with the Met Police and other constabularies.