Sid, this is not as easy as you may think with the stuff from Warton. This is not a case of going to Maplin and buying a transmitter to steal the UAS as it gets closer to you than it is to the operator.
And just how much so these Warton military grade/spec UAVs cost?
Once a real procurement quango is in operation, it would quckly find they would be prohibitively expensive, especially when you add in the crewing requirements, which I think you'll find match what we have now operating real aircraft.
You don't need to go to maplins for the hardware, china based companies can provide jammers cheaper. It
is as simple as that :-)