Notaboffin,
Probably this bit on the Beeb site
But it's not just the cost of the two aircraft carriers that concerns MPs, said the BBC's defence correspondent Jonathan Beale, but the new jets that will fly off them and the other warships needed to protect them.
The availability of ships to protect the carriers may also limit how they can be used and there are still technical and cost challenges for the new F-35 jets, he added.