It works like that - during a peace time Air Tanker is offering their a-bit-heavier-than-normal a330 to some commercial airlines at silly rates thus damaging the market, and in war time they will be sitting on the ground as civilians cannot go combat zones. A perfect case for MOD - yes we have a modern equipement, yes it costs us much less than otherwise, yes we utilise resources effeciently. All good. Before there is a real war. All well described by General Sir Richard Shirreff in his book