Bastardeux,
Your points have some validity, although I could argue against some of them, and you are obviously well informed - but I don't want to turn this thread into a long winded economic discussion, if for no other reason that people wouldn't read it! I was simply trying to point out to the "....lets go out and spend £3Bn on MPA, base them at Waddo, it'll be done by 2020, job done...." fraternity some of the economic and political constraints that any major expenditure on Defence is actually working within, i.e. what its like in the real world.
In the real world:
There's an election due in 2015, before any SDSR presumably. The next government could well be Labour, or Labour/Liberal Democrat. In which case all previous bets on Defence spending/priorities could be off/re-assessed/delayed considerably while they think about it.
SDSR 2015 isn't a given, just a plan the current government is working towards.
Money for the Defence budget is tight, and is at risk of its own project overruns (final cost of the 2 carriers, cost of JSF, etc....). There are also assets already in service, I'm thinking mainly Sentinel, that aren't funded post 2015, but CAS wishes to try to maintain. Trying to keep these could soak up any "spare" money in the Defence budget, if there is any!! (It now looks as though you can add buying a 9th C-17 to the list of items which could use up any "spare" money)
A "yes" vote in the 2014 Scottish vote for independence would have a major impact on the Defence budget, apart from simply decreasing it, in terms of what assets go where, paying for base closures, redundancies, the possible cost of re-basing SSBNs in Plymouth, etc. Separation would also have economic impacts, it could also effect the strength of the pound, especially if some sort of Sterling Zone is formed, the remainder of UK might end up shouldering a higher proportion of national debt than expected after the split, etc
Defence simply isn't a vote winner. Any spare cash, whichever party has a hold of the purse strings, is likely to go into the standard sacred cows of Education and NHS, with the new priority of "upping peoples living standards" by trying to put money back in their pockets (perhaps by funding green policies from general taxation as opposed to fuel bills, upping personal allowance, dropping basic rate of tax or VAT, etc). For example:
BBC News - Nick Clegg pushes for £1bn income tax cut
Government Deficit reduction remains a political priority, and we aren't out of the woods yet.
This is the sort of background, and with no perceivable maritime threat as far as the public are aware, against which people are envisaging finding £3Bn+ to fund a new aircraft, infrastructure, support system, recruit and train crews, etc, without losing anything else from Defence to pay for it!
I just think the rose tinted specs need to come off. I think it highly unlikely that against the background I have highlighted, Defence will be able to "find" the funds for a major buy of up market MPAs, as opposed to 4 Casa-235s. If you want MPA, what big ticket item are you willing to lose in exchange, E-3D, SH fleet, etc? All of these are sacred cows in their own right, and, although the situation with MRA4 maybe made the decision easier, this trade off decision is one which the MPA has already lost once in SDSR2010.