Dog theft is very much in the news at the moment, but, even if a dog escapes or wanders off, getting them back to their owners is made much easier by them having an up to date ID tag. In fact, it’s actually a legal requirement for a dog to carry an ID tag with owner’s address and phone details. See link below.
Also, very much recommended, is to have them microchipped so owners can easily be traced via a scanner if the unthinkable happens. You can have this done at your local vet and the RSPCA sometimes offer low cost microchipping sessions.
For your interest, here is the latest Dog Control Order published by Leeds City Council.