This picture is of a slightly roughly handmade cutaway cylinder. The only way to become a good locksmith is to love locks, and love, in this case, means destroying the occasional lock to see what makes that particular brand tick.

This is one of the new UAP British Standard (you can see the Kitemark) euro cylinders. Protection against bumping and snapping, drilling and pulling, as well as more subtle attacks such as combs and picking, are all built in.

So, in order to keep my promise to our customers, that if I drill, snap, pull or otherwise wreck your lock on your door, I will give you a replacement for free, I have to make sure I am good enough to open it with no damage. And so, this lock has been sacrificed for the greater good!