Biggus
As HAS59 said, there is money being spent all over the country, that's why we are still borrowing about £120Bn a year!!
Yet your link is suggesting we will undershoot our borrowing forecast by as much as £15 billion...making 2013 borrowing £105 billion, which as a raw figure is pretty terrifying, but considering it was knocking on the door of £180 billion (off the top of my head) 3 years ago, then that's actually quite re-assuring. Furthermore, the deficit doesn't have to be £0 before the overall national debt starts falling. Additionally, inflation, exceptionally low interest rates and a comparatively strong pound will have a very strong part to play in devaluing the long-term bonds and securities that the government has and will continue to issue. Contrary to popular opinion, moderate amounts of debt are positive - like the 40% stated - for sustaining aggregate demand in a modern, globalised economy; the UK is extremely unlikely to ever get to 0% national debt.
Plus, maybe the MoD might be able to afford more gear than we initially thought if we continue to undershoot our own budget by £2 billion a year...
And finally, the point was made that any purchase would be looking at IOC in the 2020s...I'm very confident that money will no longer be under the lock-down that it is at the moment.
Just my 2 cents