"The use of mobile phones on board aircraft by flight crew, cabin crew and passengers presents a source of uncontrolled electro-magnetic radiation with a risk of adverse interference effects to required aircraft systems including those used for communications and navigation."
UK CAA.
I think the CAA know what they are talking about!
Well, recently I was paxing to SYD aboard a [non British] B777 [configured for inflight mobile phone use] where everyone awake was happily using their cell/mobile phones.
