With regards to the UK's ability to afford 1billion in overseas aid - we should look at the UK's GDP. For 2008, it was $2,674,085,000,000 ($2.6trillion) which at today's exchange rate is �1,658,451,566,654 (�1.6trillion).
So 'giving away' �1billion, is the equivalent of passing on 0.06% of our dosh.
This is like someone who earns �20,000 a year giving �1 per month to charity.
Not exactly breaking the bank is it?
(By the way, maths isn't my strong suit, so I'm happy for anyone to challenge me on my fugures, and I'm not 100% sure of my comparison of GDP to a salary - but you see where I'm going).