But does it really cost £4million to train a P8 or Voyager pilot JTO? I deliberately left F35 out since that's outside my field but my employer was involved in training some current RAF Voyager pilots and the bill didn't come to even a small fraction of £4 million. In any case your 28 year pilot (really?) still needs training up on P8/330/F35 which you haven't costed.
Have the services EVER strived for retention? Im not saying it's right, by the way but we used to have National Service pilots and that's back in what many here would call the good old days.