well insurabce itself is a con in my eyes. but hey ho.
many people through the years felt it was a nice little earner to lob in a 50 quid claim here and there, and so the insurance co's decided to say, well ok, you pay for the first 30 quid and you can have 20, as a way of preventing spurious and minor claims.
this turned into a nice little earner for the insurance co's so they thought, well how about we say you pay 4 and we pay 5, this turned into hundreds and so the story begins.
its amazing how low you can get your insurance (on compare websites) just by paying increasing the large wedge of "excess" from your own cash pot and saving the insurance paying out. clever that isnit.