The overseas aid budget will increase by an extra £1 billion over the next two years under new European Union rules, it has emerged.
The Department for International Development (Dfid) is preparing to change accounting methods in order to bring Britain in line with other EU countries, making it harder to meet the controversial aid target in the next parliament, according to The Times.
The UK already spends more than any other country on international agencies and is the second largest aid donor in the world.
Government figures released on Thursday reportedly show that Britain met last year's aid spending target of 0.7 per cent of GDP, totalling £11.7 billion.
They showed that most of the extra cash had gone to international aid agencies rather than projects run by the British government on the ground.Plans to increase the aid budget were branded "absurd" by several former Tory MPs, who said the money would be much better spent on protecting the armed forces.
Sir Gerald Howarth, former Tory defence minister, told The Times: "What is the point of this arbitrary figure of spending 0.7 per cent of GDP?
"The idea that if we spend this amount all the world's problems will end is so absurd, or that by providing that magic figure we suddenly become paragons of virtue.
"If a change in the formula means the British taxpayer has to contribute yet more in overseas aid despite five years of austerity a lot of people will start questioning the largesse of this country," he added.
"There are many military figures who just don't see the logic of putting money into aid instead of defence."