Aid charities have applauded Chancellor George Osborne's decision to make good on Britain's commitments to help the developing world.
But Mr Osborne's confirmation that the UK will hit the United Nations target of spending 0.7% of national income on aid by 2013 sparked anger in some quarters.
The right-of-centre Adam Smith Institute thinktank said it "beggars belief" that the Department for International Development should enjoy a boost in its budget at a time when the police, universities and the armed forces are facing cuts.
DFID's resource budget will increase by 37% in real terms to £9.4 billion by 2014/15 - the largest rise of any Whitehall department - while its capital budget will grow by 20% to £2 billion. The UK's official aid of £12.6 billion - including spending by other departments - amounts to 0.7% of the UK's predicted GDP in 2014 - up from 0.56% this year.
Mr Osborne said that the increase would make the UK the first major country to meet the UN target, set in 1970.
"This coalition Government will be the first British government in history, and the first major country in the world, to honour the United Nations commitment on international aid," he told MPs.
The spending includes up to £500 million a year on tackling malaria, with the aim of halving the number of deaths caused by the disease in 10 of the worst-affected countries.
DFID will also prioritise conflict resolution, as well as improvements in child and maternal health designed to save the lives of 50,000 pregnant women and 250,000 newborn babies.
But it will halt aid programmes to China and Russia. In 2008-09, China - the world's third-biggest economy - received more than £40 million from the UK, while Russia got £190,000.
"Whether working behind the counter of a charity shop, or volunteering abroad, or contributing taxes to our aid budget, Britons can hold their heads up high and say - even in these difficult times, we will honour the promise we make to the very poorest in our world," Mr Osborne said.