British arms sales to Saudi Arabia are causing “significant civilian casualties” in Yemen and are probably illegal, a damning parliamentary report says today.

Theresa May’s refusal to curb weapons exports has been condemned by peers who conclude it is “on the wrong side” of international humanitarian law.

The prime minister has faced down calls for a ban – on sales worth a staggering £4.7bn since the brutal war in Yemen began in 2015 – despite the growing humanitarian disaster.

An estimated 85,000 children under the age of five have died from extreme hunger or disease in a war between a Saudi-led coalition and Iran-backed rebels. Up to 14 million people are at risk of famine.

Independent experts have highlighted “extraordinary rates of civilian deaths by airstrikes” carried out by the Saudi coalition, with about 166 people dying every month last autumn.

Now the House of Lords International Relations Committee says the prime minister must rein in arms sales to Riyadh “as a matter of urgency” – describing the situation in the country as “unconscionable”.

“We do not agree with the government’s assertion that it is narrowly on the right side of international humanitarian law in the case of licensing arms exports to the Saudi-led coalition,” said Lord Howell, its Conservative chairman.

“It is narrowly on the wrong side: given the volume and type of arms being exported to the Saudi-led coalition, we believe they are highly likely to be the cause of significant civilian casualties in Yemen, risking the violation of international humanitarian law.

“The government must address the root causes of the suffering – the conflict itself – and be prepared to suspend some key export licences to Saudi Arabia and members of the coalition.”

Children suffering from acute malnutrition in Yemen Show all 17 1 /17 Children suffering from acute malnutrition in Yemen Children suffering from acute malnutrition in Yemen Doctors take some blood of Yemeni Yousef Abdullah Bakhit Ali, 13, suffering from severe acute malnutrition. With ongoing and unending conflict in Yemen, humanitarian situation continues to deteriorate across the country Unicef/Huwais Children suffering from acute malnutrition in Yemen A doctor weighs Yemeni baby Yahya Hamoud Ali Al Huzef, 9 months suffering from malnutrition Unicef/Huwais Children suffering from acute malnutrition in Yemen Ali Mohammed Ahmed Jamal,12 years old and suffering from severe acute malnutrition. He arrives with his family at a Unicef supported treatment centre in a hospital in Sanaa Unicef/Huwais Children suffering from acute malnutrition in Yemen A doctor measures the arm of Yemeni Ali Mohammed Ahmed Jamal, 12, who is suffering from malnutrition at a treatment centre in a hospital in Sanaa Unicef/Huwais Children suffering from acute malnutrition in Yemen There are over 400,000 severely malnourished children in need urgent lifesaving assistance in Yemen Unicef/Abdulhaleem Children suffering from acute malnutrition in Yemen Ali Mohammed Ahmed Jamal is weighed Unicef/Huwais Children suffering from acute malnutrition in Yemen A doctor measures the arm of baby Yahya Hamoud Ali Al Huzef Unicef/Huwais Children suffering from acute malnutrition in Yemen Unicef are currently working to reach 275,000 malnourished children with critical life-saving supplies and care for over 5 million people with safe and clean water to stop the spread of life-threatening diseases Unicef/Huwais Children suffering from acute malnutrition in Yemen Yahya Hamoud Ali Al Huzef with his family in his house in the outskirts of the capital Sanaa Unicef/Huwais Children suffering from acute malnutrition in Yemen The country is on the brink of famine and children's chances of survival are becoming slimmer by the day Unicef/Abdulhaleem Children suffering from acute malnutrition in Yemen Ali Mohammed Ahmed Jamal has his arm measured Unicef/Huwais Children suffering from acute malnutrition in Yemen Unicef are currently working to provide nearly 1 million children with vaccines and healthcare Unicef/Huwais Children suffering from acute malnutrition in Yemen Doctors take some blood of Yemeni Yousef Abdullah Bakhit Ali, 13 years old suffering from severe acute malnutrition at a treatment centre in a hospital in the capital Sanaa on November 2, 2018. (Release obtained) With ongoing and unending conflict in Yemen, humanitarian situation continues to deteriorate across the country. There are over 400,000 severely malnourished children in need urgent lifesaving assistance in Yemen. The country is on the brink of famine and childrenâ€™s chances of survival are becoming slimmer by the day. UNICEF are working with partners around-the clock to save children suffering from malnutrition and disease. We are currently working to reach: â€¢ 275,000 malnourished children with critical life-saving supplies and care â€¢ Over 5 million people with safe and clean water to stop the spread of life-threatening diseases â€¢ Nearly 1 million children with vaccines and healthcare â€¢ 9 million people with emergency cash assistance to help families buy basic commodities so they can survive Â© UNICEF/UN0253367/ Huwais Unicef/Huwais Children suffering from acute malnutrition in Yemen Unicef are working with partners around-the clock to save children suffering from malnutrition and disease Unicef/Abdulhaleem Children suffering from acute malnutrition in Yemen Unicef are currently working to provide 9 million people with emergency cash assistance to help families buy basic commodities so they can survive Unicef/Huwais Children suffering from acute malnutrition in Yemen Ali Mohammed Ahmed Jamal is suffering from malnutrition Unicef Children suffering from acute malnutrition in Yemen On 31 October 2018 in Yemen, the Al Thawra Hospital in Hodeidah where children are being treated for severe acute malnutrition. UNICEF Regional Director for Middle East and North Africa Geert Cappelaere visited Yemen from 29 October through 1 November 2018. As of 30 October 2018, over 11 million children â€“ 80 per cent of all children in the country â€“ require humanitarian assistance, due to the impact of the ongoing conflict. Worsening years of underdevelopment, attacks against civilians and civilian infrastructure and lack of salary payments for most civil servants have pushed basic services for children to the brink. Children face food shortages, disease, displacement and an acute lack of access to basic social services. One out of three children in Yemen is at risk of acute malnutrition. Â© UNICEF/UN0253574/Abdulhaleem Unicef/Abdulhaleem

The report calls on the government to:

* Stop “relying on assurances by Saudi Arabia” that UK weapons are not being used in breaches of international humanitarian law

* Warn the regime, and Iran, that failure to back the Stockholm Agreement – which agreed to a partial ceasefire – “would have negative consequences”

* Provide greater support to the United Nations’ secretary general for Yemen and throw its weight behind the UN peace process

* Stand ready to use its role as “penholder”, or chairman, at the UN security council to “intervene if peace talks are not progressing and if blockages arise”

Jeremy Corbyn has demanded a ban on arms sales to Saudi Arabia, pointing out that “Germany, the Netherlands, Norway and others” have already done so.

But ministers have insisted that exports are assessed “against strict criteria” and stopped if “there is a clear risk that the items might be used in the commission of a serious violation of international humanitarian law”.

Quizzed in the Commons in December, the prime minister ducked the controversy, insisting: “The question of providing for those people who are suffering terribly in the Yemen today is about ensuring that there is a political solution ​in the Yemen.