Already accounted for in other budgets, international commitments, strategic partnerships, trade deals between UK firms and recipient countries, arms deals, war against the taliban etc etc
There is plenty of money to be spent - mostly here at home. Despite the 'cuts' govt spending will continue to rise over the next three years.
Like any budgeting exercise you have to make judgements about the benefits/risks of allocating/not allocating in certain areas over a long period.