Here is a story that may interest you concerning the future funding of Britain's armed forces.
David Cameron: Tories could use aid money for defence budget - Telegraph
A paragraph that captures the essence of the story:
"..some Tories believe the party can honour that pledge [ 0.7% of GNP on aid] by counting some spending done by the Ministry of Defence as development aid, since the work of the Armed Forces contributes to the development of countries like Afghanistan"