Nurse, IIRC the nuclear deterrent bit of the budget actually has very little to do with the navy, and is kind of ring fenced off. It's regarded as a national toy rather than matelot's, so suspect that they wouldnt be forced to make that choice, as anyone in their right mind would say "why thankyou m'lud, we'll take the carriers" and let the politicians throw up their arms in uproar and the lack of credible deterrent...