I do think that the UK should give foreign aid. Just not to countries who harbour terrorists, have nuclear weapons and spend vast amounts of their money on military hardware whilst effectively ignoring their own massive poverty problem.
Huderon suggests that we should give aid in order to give their kids a better education by setting up schools which don't teach hard-line fundamentalist religious philosophy. I agree. Unfortunately, the money we send in aid is out of our sphere of influence once it has been received – the recipient country can spend that money on anything they see fit. Even if we stipulate that certain aid monies should be spent on x, y and z (as SandyRoe suggests), there is nothing to stop the recipient country from performing a little bit of financial wizardry that on paper looks like they're fulfilling their obligations.
Rather like the UK Road Tax, the money is ostensibly funnelled into the maintenance of the country's highway infrastructure. In reality, this money simply goes into the 'pot' and is used for whatever purpose is deemed necessary by the Government.
In short, yes we should give financial aid to foreign countries.
But only to those countries we can be relatively sure are not actively engaging in or are sympathetic to terrorism against the UK or its allies. The current Pakistan Government fails on both counts.