Not some branch of the security services but the venerable “Post Office Lock”. I assume it is so named because it was either used on postboxes or on the drawer at counter positions in post offices. But if anyone does know, do please leave a comment.
Anyway, the CT12 is a seven lever lock with no symmetry* and I picked one open today – yay! It was on a gun cabinet where the key had been lost. This is fairly common around here. If ever there needs to be a popular uprising in Clapham, we certainly are armed to the teeth, with shotguns seemingly in every other house.
Twenty years ago, the post office lock was found on lots and lots of low-security safes. It was well made and difficult to pick, so manufacturers have tended to abandon it for cheap locks from Wun Hung Lo. It is still found on gun cabinets though, where it is one of three locks that you commonly encounter: the 2802 which is difficult but for which one can make a dedicated pick, the “Ace” which is easy to pick with the general purpose pick, and the post office lock which is difficult (it has large, tight false gates, in case you want to know). So I was very pleased – even in my state of advancing decrepitude – eighteen months from retirement – to pick it.
* In your front door’s five lever lock, two levers will be the same. This is so that the key can work from both sides without being impossibly wide. And knowing this means that picking five lever locks is slightly easier.