Its perfectly legal to own a scanner in the UK. I was going to post the same link as above. Please be certain of facts before making stern statements!
However,what is illegal is listening to airband frequencies..but if the regutlatory authority were to enforce that, there would be thousands of prosecutions, in view of the number of people seen using them at airports, airshows and the like. As usual over here..its an archaic law that makes no sense, is ignored by most, and has not caught up with the 20th century, never mind the 21st!!