Hugh, IO540 and others...
If the device appears on your aircraft's radio licence you are entitled to use it in the aircraft.
If it does not appear on the aircraft's radio licence it is not licensed, and you may not use it. Check the relevant Act, which BEagle has already quoted, and then stop trying to squirm out of the regulations.
And IO540, if you can point to any document stating that you mobile phone is licensed I will be most astonished. I have bought many mobile phones in my time and I have never seen, nor applied for, nor been given, sold or otherwise obtained a licence for any of them.