Not to mention, my ever so charming home town experienced a spate of vicious in-car robberies last year. The victim stops at a junction or traffic lights, at which point hooded/masked yobs open the passenger and/or rear door, throw a Rottweiler at you, then smash your face in with a brick before removing any valuables and legging it.
Locked doors for the proverbial win!
...if you're scared of getting car jacked in England you have serious paranoia issues.
Or just live in a place where this stuff happens.