I thought that the Florida student who tried to recreate September 11th with a Cessna did a good job of demonstrating that a light aeroplane was about as useful to a terrorist as a chocolate teapot. If all you can do is break the window of a tower block you aren't going to do much to a reactor, are you? Sugar or no sugar.
And yes, I hope the CAA get involved too - or are they only interested if you fly 499 feet over old Mrs Miggins on a sunday afternoon?