International development secretary Penny Mordaunt has been criticised by charities including Christian Aid for suggesting Britain's commitment to spending 0.7 per cent of gross national income on aid is 'unsustainable'.

Mordaunt, who is tipped as a prospective candidate in Conservative Party leadership elections, has said private funding should be part of the target. She has also said Britain's aid spending should be more closely aligned to its strategic goals.

Christine Allen, director of policy and public affairs at Christian Aid, said: 'Politics is already causing huge uncertainty for so many people in Britain. Now is not the time to cause further uncertainty for the world's poorest by playing politics with Britain's commitment to international aid.

'"We believe Britain's aid budget is a badge of honour worthy of pride and fierce defence. We are saddened that Penny Mordaunt is not eagerly fighting to maintain and even increase the 0.7 per cent aid commitment given the rising number of people in dire need in Yemen, Syria, and many other emergencies around the world.

'When heads of government, faith leaders, celebrities and the British public themselves are recognising the dire need in our world, we expect our DFID Secretary to stand with them and celebrate Britain's determination to end poverty, and never bow to naysayers.'

She said that 'even the idea of withdrawing from these international commitments to development is deeply damaging'.

Tory MP Anna Soubry tweeted: 'First Brexit now foreign aid. Not so slowly the Conservative party moves to the right.'

A Downing Street statement said: 'The commitment which we have to foreign aid is set down in statute. It remains unchanged, there are no plans to change it. The secretary of state has discussed publicly that she is looking at the aid process and making sure the money from taxpayers is being used in the most efficient way and gets the greatest contribution.'