Keys In Locks
It’s not a good idea to leave keys in lever locks. I remember back when I was a student, in a shared house, and responsible for my own security for the first time, assuming that as long as there wasn’t a gap under the door big enough for the pencil and sheet of newspaper trick, that leaving the key in the back door would make it more difficult to pick open. (We are talking about a lever lock here — where the key disappears inside a traditional keyhole.)
Little did I know. Firstly, almost no thieves pick locks — certainly not those of student hovels just around the corner from the Coronation Street set in Salford — they just break the door or the frame. Secondly, it actually makes it easier for the thief who knows what he or she is doing (so still pretty rare) to open the lock.
Profile cylinder locks are different, however. As long as there’s no letter-slot — and surely no-one these days is going to leave a key anywhere near a letter-slot — a key left in the inside keyway of a keyed-both-sides profile cylinder (of the kind usually found on uPVC doors) makes it much more difficult to pick open the lock. Or for that matter, even to open the lock normally. In fact it’s a prime cause of people becoming locked out.
