A senior Conservative has said that British prime minister Boris Johnson is refusing to give MPs a say on cuts to Britain’s humanitarian aid budget because the government would lose a vote on the matter.

“The government wouldn’t be trying to avoid a vote if they thought they could win it,” former Tory minister Chris Patten told openDemocracy.

“The government increasingly gives us the impression that when they say taking back control they don’t mean Parliament having control, they mean the Executive having control, with as little control for Parliament as possible,” he added.

Patten’s comments add to the pressure on Johnson to hold a parliamentary vote over the decision to cut Britain’s legally binding aid target from 0.7 to 0.5% of gross national income.

Last week documents leaked to openDemocracy revealed details of the drastic cuts in British humanitarian aid to some of the world’s poorest countries.

Proposals from the Foreign, Commonwealth and Development Office would see aid to Syria fall by more than two-thirds. Assistance to Libya would fall by 63%, Somalia by 60%, South Sudan by 59% and Lebanon by 88%.

The British government has said the reduction in aid spending is “compatible” with existing legal commitments and does not require a vote in Parliament.

Tory MPs opposed to the foreign aid cuts have said that they will back a legal challenge if the government refuses to hold a vote on the proposed multi-billion-pound aid cuts.

Some sources have suggested that the British government is attempting to put off a parliamentary vote on aid cuts until after the G7 summit in Cornwall in June due to “reputational concerns”.

Patten described the planned aid cuts as “very bad all round”, especially during the global pandemic.

“I think it is very bad in terms of what we can do as a country concerned about humanitarian assistance, very bad for what we can do in continuing to strengthen our reputation as a global development power and it is also particularly damaging in this moment when we should be doing more for poor countries hit by the coronavirus,” he said.

The former Hong Kong governor said that the cuts would fall disproportionately on “places where we presumably want Britain outside the European Union to have the ability to make its mark”.

“We keep on blowing the trumpet about being ‘Global Britain’. At the same time we have announced subsuming the highly regarded international development ministry into the Foreign Office and cut its budget by a huge amount. That doesn’t seem to me to be a very good way of striding [onto] the world stage,” Patten said.

Labour MP Sarah Champion said that the British government had shown a “complete lack of regard for the democratic process” in refusing to hold a vote on the aid cuts.

“The government hasn’t shown any transparency throughout the process of its cuts to aid. The debates in Parliament have been because MPs called them, not because the government granted them,” Champion, the chair of the international development committee, told openDemocracy.

Overall Britain’s aid budget is due to fall from about £15bn before the pandemic to £9bn this year, owing to the smaller size of the post-COVID economy and the 0.2% reduction in Britain’s commitment to aid spending.

The head of the UN’s Office for Humanitarian Affairs, former British civil servant Mark Lowock, has accused the government of “balancing the books on the backs of Yemen’s starving children”, while former international development secretary Andrew Mitchell, who was involved in drawing up the commitment, said he would back a challenge in the courts if ministers failed to seek parliamentary approval.

“If the government wants to change that, MPs need to vote on it. And if we don’t get a vote it will go to court. Then the judge will look at what parliament intended and that is very clear,” Mitchell told The Times.

Asked whether the government would support a Commons vote on the cut, 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.”

After the cuts were announced in November, foreign secretary Dominic Raab told the Commons: “It’s very clear [that] if we cannot see a path back to 0.7[%] in the foreseeable immediate future and we can’t plan for that, the legislation would require us to change it, and [we] would almost certainly face [a] legal challenge if we don’t carefully follow it.”

Responding to a question about legislation on the reduction of the aid 0.7% target on Tuesday, Treasury minister John Glen told the Commons that Raab was “continuing to look very carefully at the legislative requirements” and that the government would set out more detail “in due course”.