Yep, I can remember the last time it happened within the Met., in the aftermath of the 3 coppers being shot in Braybrook Steet, and in the subsequent search for Harry Roberts. I did think though that in the Met it was only the known ex-servicemen that were issued, although back in 1966, there weren't a huge number serving then that hadn't seen service, given National Service had only ended 5 years earlier.
My old man was a dog handler at the time and a WW2 vet, and when they were using the dog section to search a lot of the fields/farmland out to the west and north-west of the Met district, searching for Roberts, Dad was issued with one of the old Webley's, and I can remember as a wide eyed kid, him bring it home on a few nights much to my Mum's astonishment. It was the only time my old man carried an issued firearm during his 30 years of Met service.
It was as a result of Braybrook St, that prompted the Met to create a specialist firearms unit.