I wonder if MoD really knows the true cost of through-life support; of any aircraft.
One of the obvious things to "emerge" post-Haddon-Cave and formation of the MAA is that safety regulations must now be followed, whereas for 20 years it has been deliberate policy not to implement them, in the interests of "saving" money.
The upshot is that expenditure must increase at a time when the Defence Budget is being squeezed. Given it is 20 years since this was properly funded, how many people in MoD can even scope the actual requirement, never mind cost it? The only Def Stan containing the detailed procedures was scrapped 2 years ago. MoD haven't been able to provide a copy of it to staff since 1993 so there is nothing in the archives to look at.
There is a huge wheel to be reinvented. This constitutes a huge variable in the budget. Platform (not just aircraft) and Equipment IPTs are being asked to cost their "new" post-Haddon-Cave workload. Most are struggling, because they haven't a clue what is necessary. MAA audits are revealing crap Safety Cases by the bucketful but, witnessed by the Nimrod case, there is little corporate knowledge on how to resurrect them and the related disciplines. The bean counters will be seeing "TBA" all over these costings and, in their mind, the solution is to get rid of some variables - which means whole fleets.