Part of Britain's £6bn overseas aid budget could be switched to defence and anti-terrorism projects, according to a leaked government document.
The proposal could undermine the Coalition Government's repeated pledges to increase spending on aid to the world's poorest countries. While other ministries will see their budgets cut by up to 40 per cent in a spending review to be concluded by October, the Department for International Development and the Department of Health have been promised more money each year on top of inflation.
The leaked report discloses that the National Security Council (NSC), chaired by David Cameron, has ordered that the ODA (official development assistance) budget should make "the maximum possible contribution to national security".
It adds: "Although the NSC will not in most cases direct DFID spend in country, we need to be able to make the case for how our work contributes to national security."
The report, sent to DFID offices abroad, advises officials to mention national security when submitting bids under a new internal market for aid projects. It adds: "We need to explain how DFID's work in fragile states contributes to national security through 'upstream' prevention that helps to stop potential threats to the UK developing (including work to improve health and education, provide water, build roads, improve governance and security)."
Labour seized on the leak as evidence that spending on relieving poverty could be cut, possibly to ease the cash crisis at the Ministry of Defence.
Gareth Thomas, the shadow minister for International Development, said: "This document is deeply worrying as it confirms the fears of many in the international development and humanitarian community that the Government plans to securitise the aid budget, and weaken its focus in prioritising resources on the poorest people and countries."
He claimed that other ministers, rather than the Secretary of State for International Development, Andrew Mitchell, would now call the shots on the aid budget.
"It is right that our development and national security efforts are complementary and co-ordinated, particularly in countries like Afghanistan, but there is a significant risk that we will see our aid budget increasingly geared to narrow security priorities, instead of meeting the wider needs of the poorest and most vulnerable people," said Mr Thomas.
He said that it was becoming clearer why the Tories had abandoned more than 80 of Labour's key international commitments – including a pledge to put millions more children into school – as fewer resources will be available if money is switched to security. "With a key UN summit less than a month away this will be a further blow to those hoping Britain would be leading the effort to get the Millennium Development Goals back on track," he said.
A DFID spokeswoman said: "Relief of poverty is central to everything that DFID does. But countries most struggling to come to terms with the battle against poverty are precisely those where conflict and insecurity are most prevalent. Unless the international community takes a lead in tackling these intractable problems, we cannot hope to achieve a better deal for the world's poorest people."
She added: "A review of all the UK's bilateral aid is looking at all DFID's programmes, but has yet to reach any conclusions. All DFID funding is and will continue to be governed by internationally agreed definitions of what constitutes aid".