Britain has been accused of padding its aid budget with "made up money" so it can claim to have met its millennium promise of increasing the amount it donates to the world's poorest people.
The Department for International Development, headed by Andrew Mitchell, has confirmed that cancelling the debts of some of the world's poorest countries will count towards the aid total, helping the UK to achieve its millennium target of spending 0.7% of national income on overseas aid by 2014.
One of the most controversial debts is the millions that the Sudanese nominally owe for weapons purchased during the Cold War.
In the late 1970s, the west was arming Sudan as a counterweight to the Marxist regime in neighbouring Ethiopia, which was backed by the Soviet Union.
The debt is expected to be cancelled in 2013-14, a formality which will instantly add 7% to the UK's nominal aid budget.
Tim Jones, the senior policy officer at the Jubilee Debt Campaign, said: "The debt should be cancelled because it is unjust and unpayable, not used to meet targets and massage figures."