Go for it Beagle!
A definitive ruling from the CAA? You will not live long enough to receive it. By the time it emerges from the Belgrano`we'll be using an entirely different technology. Remember that building is populated by Meldrews - none of whom got where they are today - by ever making a definite ruling that could be traced back to them! (to mix my quotes).
Keef has a useful (and very relevent!) observation. There are many legal roles which do have the ability to set precedence or rulings. Hence not granting permission for something would make things illegal through that authority - much air traffic legislation works on this principle for instance.
So do ask the CAA for the definitive legal reference which prohibits to use of mobile phones - of all the Meldrews they should be the most capable!