In the UK, no matter how well you can steer with your knees, the police do not accept that you are in proper control of your vehicle. You must have a properly adapted vehicle, and be in control at all times. If you are caught driving without your hand on the wheel (ie: when changing gear, or operating the indicators, etc) they will throw the book at you. And God help you if you cause an accident and hurt someone !
I always have a good look around to make sure there are no coppers about before I unwrap my Mars bar, scratch my nose, or read the paper !