jez,
Check the numbers. You would get 18 C-17s for your 25 A400m's.
I posted the figures to provide a simplistic cost comparison. I would not go down the capability road if i was arguing for the A400m over the C-17. Halving the number of C-17's in a direct comparison was a neat, if incorrect, trick.
What would you rather have? 18 C-17s or 25 A400m...?
Ottb is correct to point out that the real solution would involve both J and Globemaster, types we already operate.
Without stating the bleeding obvious, can we now afford to waste such a huge sum of money propping up a failed contract. If we opt for A400m, the money is not going to come out of social security. Therefore, paradoxically, an insistance on its procurement could harm defence.
Sad to say it but; nice aeroplane, wrong time, poor contract.