Well the tax bill is large. All that money seems to be going on (mis)management and PPFI handouts. A more speculative approach to housing (build council houses and sell them off) might take some pressure out of the housing market and help the coffers of the exchequer. An iron fist on the more free spending departments (relatively) might leave some fiscal room for manouver at the MoD. Even then, we would have to hope that it doesn't get spent on more armchairs for Whitehall and EDS computer contracts.

I'd be happy with a 0.5% of GDP increase ramped up by 0.05% each year for ten years. The first extra 0.05% of GDP would be spent entirely on marketing aimed at justifying greater defence spending. Especially on hard to explain notions like the benefits of a blue water navy.