Downing Street has suggested MPs may not be given a vote on the cut to the foreign aid budget, as Tories threaten to rebel against the controversial move.

Conservative former minister Andrew Mitchell urged the Government on Monday not to “shy away from a vote because it is rightly scared that it may be defeated”.

No 10 argued that the cut from the legally-binding target of 0.7% of gross national income (GNI) to 0.5% is compatible with existing law.

And with rebel sources confident the Government would be defeated, the Prime Minister’s spokesman declined to commit to giving MPs a vote on the plan.

Instead, the spokesman argued a vote was not necessary by arguing the move is compatible with the 2015 law that sets the aid target.

Pressed if No 10 is for or against a Commons vote, Boris Johnson’s spokesman said: “The Government is acting compatibly with the International Development Act which explicitly envisages there may be a circumstance where the 0.7% target is not met.”

He added that Foreign Secretary Dominic Raab would set out the next steps in “due course”.

Mr Mitchell, a former development secretary, said the law only provides for reductions in “unintended and retrospective circumstances, not premeditation”.

He told the PA news agency: “Clearly the Government cannot deliberately break the law on 0.7% without parliamentary consent.

“The Government needs to have the courage of its convictions on this matter and not shy away from a vote because it is rightly scared that it may be defeated.

“We are a generous country and the 0.7% is not just a promise to the poorest, it was also a manifesto commitment from every single member of the House of Commons elected just over a year ago.”

Tobias Ellwood, the Conservative MP who chairs the Commons Defence Committee, also urged the Government to allow a vote, or face a defeat through other means, such as through related amendments or opposition day debates.

He told PA: “If there is no Government vote on this matter the view of the House will be tested through another legislative instrument, for which I hope the Government will play close attention to.

“By pulling programmes in places like Libya, the Russians will be delighted to see we’re stepping back, Boko Haram benefits from us withdrawing interest in Nigeria, Al-Shabab will celebrate us reducing funds for Somalia and ultimately when threats are diversifying and becoming more complex, not least with the rise of authoritarianism, brought about by extremism, this sends the wrong message for a country trying to re-establish its global credentials.”

In November, the Government announced the plan to temporarily slash the aid budget to help repair damage to public finances caused by the coronavirus pandemic.

Mr Raab has said he wants to restore it to 0.7% of GNI “as soon as possible”.

But Conservatives have joined charities, opposition MPs and former prime ministers David Cameron and Tony Blair in being angered by the move.

The development came as the United Nations’ top humanitarian affairs official condemned the Government for slashing aid to Yemen.

Mark Lowcock, the head of the UN’s humanitarian affairs office, said the UK’s move was “an act of medium and longer term self-harm, and all for saving what is actually – in the great scheme of things at the moment – a relatively small amount of money”.

“The decision, in other words, to balance the books on the backs of the starving people of Yemen, has consequences not just for Yemenis now, but for the world in the long term,” Mr Lowcock, a former Department for International Development permanent secretary, told the Guardian.

The UK has pledged at least £87 million in aid to the Middle Eastern country, down from a promise of £160 million in 2020 and £200 million in 2019.

The Prime Minister’s spokesman responded: “We would reject that characterisation. We continue to play a leading role in fighting famine and hunger around the world.”