Derek, yes it was Cellnet, and before that it was Securicor, opps, showing my age.
My brother worked in telecoms most of his life, before the Brick went on sale, they tested it by running over it with a car. It still worked.
My other brother was once standing in a queue for the waltzer with his young daughter on may day about 7 year ago when a mobile shot out of a girls hand bag on the ride, hit him square on the nose and knocked him out. worst was the call wasnt for him

Andrew