The government has stopped approving the sale of weapons that could be used in Yemen after its processes were ruled unlawful by judges.

Liam Fox, the international trade secretary, said the government would challenge the Court of Appeal ruling but it had suspended new export licences for Saudi Arabia and its partners in the bloody war.

Addressing MPs in parliament, he said the government applied a “rigorous and robust multi-layered process” in line with UK and EU criteria.

“We are carefully considering the implications of the judgment for decision-making,” Mr Fox added. “While we do this, we will not grant any new licences for exports to Saudi Arabia and its coalition partners which might be used in the conflict in Yemen.”

He said the judgment did “not undermine the UK’s overall framework for export controls” and that existing licences would not be suspended.

The children wounded in Yemen's war Show all 15 1 /15 The children wounded in Yemen's war The children wounded in Yemen's war Save the Children Child Protection staff pictured alongside Ahmed and his family to ensure ongoing physical and mental support for Ahmed at home through regular follow up visits. August 15, 2018 Ali Ashwal / Save the Children The children wounded in Yemen's war Ahmed, a 15 year-old, is lying on his bed after his leg and arm were injured during an airstrike in a market in Hudaydah. His leg is protected with Gypsum after several successful surgeries. Ali Ashwal / Save the Children The children wounded in Yemen's war Save the Children Child Protection staff pictured alongside Ahmed and his family to ensure ongoing physical and mental support for Ahmed at home through regular follow up visits. August 15, 2018 Ali Ashwal / Save the Children The children wounded in Yemen's war Save the Children Child Protection staff pictured alongside Ahmed and his family to ensure ongoing physical and mental support for Ahmed at home through regular follow up visits. August 15, 2018 Ali Ashwal / Save the Children The children wounded in Yemen's war Save the Children Child Protection staff pictured alongside Ahmed and his family to ensure ongoing physical and mental support for Ahmed at home through regular follow up visits. August 15, 2018 Ali Ashwal / Save the Children The children wounded in Yemen's war Ahmed, a 15 year-old, is lying on his bed after his leg and arm were injured during an airstrike in a market in Hudaydah. His leg is protected with Gypsum after several successful surgeries. August 15, 2018 Ali Ashwal / Save the Children The children wounded in Yemen's war Save the Children Child Protection staff pictured alongside Ahmed and his family to ensure ongoing physical and mental support for Ahmed at home through regular follow up visits. August 15, 2018 Ali Ashwal / Save the Children The children wounded in Yemen's war Ahmed, a 15 year-old, is lying on his bed after his leg and arm were injured during an airstrike in a market in Hudaydah. His leg is protected with Gypsum after several successful surgeries. August 15, 2018 Ali Ashwal / Save the Children The children wounded in Yemen's war Ahmed, a 15 year-old, is lying on his bed after his leg and arm were injured during an airstrike in a market in Hudaydah. His leg is protected with Gypsum after several successful surgeries. Ali Ashwal / Save the Children The children wounded in Yemen's war Iman* is six years old and lives in Altuhaitah district, Western Hodeidah, with her parents and six siblings. Her father is a daily labourer and earns around 500 – 1000 Yemeni Riyals (1 – 2 USD) each day. On 26th June, Iman was playing in her backyard when an airstrike hit her neighbour’s house. Shrapnel from the attack reached Iman’s home and she severely injured her neck, hand, and leg. Iman’s three-month-old brother also sustained minor injuries from the shrapnel. June 07 2018 Ali Ashwal / Save the Children The children wounded in Yemen's war Iman* is six years old and lives in Altuhaitah district, Western Hodeidah, with her parents and six siblings. Her father is a daily labourer and earns around 500 – 1000 Yemeni Riyals (1 – 2 USD) each day. On 26th June, Iman was playing in her backyard when an airstrike hit her neighbour’s house. Shrapnel from the attack reached Iman’s home and she severely injured her neck, hand, and leg. Iman’s three-month-old brother also sustained minor injuries from the shrapnel. June 07 2018 Ali Ashwal / Save the Children The children wounded in Yemen's war Iman* is six years old and lives in Altuhaitah district, Western Hodeidah, with her parents and six siblings. Her father is a daily labourer and earns around 500 – 1000 Yemeni Riyals (1 – 2 USD) each day. On 26th June, Iman was playing in her backyard when an airstrike hit her neighbour’s house. Shrapnel from the attack reached Iman’s home and she severely injured her neck, hand, and leg. Iman’s three-month-old brother also sustained minor injuries from the shrapnel. June 07 2018 Ali Ashwal / Save the Children The children wounded in Yemen's war Iman* is six years old and lives in Altuhaitah district, Western Hodeidah, with her parents and six siblings. Her father is a daily labourer and earns around 500 – 1000 Yemeni Riyals (1 – 2 USD) each day. On 26th June, Iman was playing in her backyard when an airstrike hit her neighbour’s house. Shrapnel from the attack reached Iman’s home and she severely injured her neck, hand, and leg. Iman’s three-month-old brother also sustained minor injuries from the shrapnel. June 07 2018 Ali Ashwal / Save the Children The children wounded in Yemen's war A boy injured by in the attack on a school bus in Saada, August 9th. Dozens of children aged between 6 and 14 have been killed with many more injured, after the school bus they were travelling in was hit by an airstrike in the town of Dhahyan in Saada governorate in northern Yemen. August 09, 2018 Save the Children The children wounded in Yemen's war A boy injured by in the attack on a school bus in Saada, August 9th. Dozens of children aged between 6 and 14 have been killed with many more injured, after the school bus they were travelling in was hit by an airstrike in the town of Dhahyan in Saada governorate in northern Yemen. August 09, 2018 Save the Children

“These criteria have stood the test of time and are shared by EU member states,” Mr Fox said. “The court’s judgment is about how decisions were made in relation to one element of one of these criteria in a specific context.”

On Thursday, the Court of Appeal ruled in favour of anti-arms-trade campaigners in the latest stage of their legal battle against the government over the Yemen conflict.

The Campaign Against Arms Trade (CAAT) argued that UK fighter jets and bombs are being used to kill civilians and violate international law.

The High Court previously ruled in the government’s favour, finding that it was “rationally entitled” to conclude that the Saudi-led coalition was not deliberately targeting civilians and was investigating reported incidents.

CAAT challenged the 2017 ruling and took fresh evidence from the Yemen conflict to the Court of Appeal, which reviewed classified material in closed hearings earlier this year.

The master of the rolls, Sir Terence Etherton, Lord Justice Irwin and Lord Justice Singh concluded that it was “irrational and therefore unlawful” for the international trade secretary to have licenced weapons exports without assessing whether past incidents broke international law and if there was a “clear risk” of future breaches.

“The question [of] whether there was an historic pattern of breaches of international humanitarian law on the part of the [Saudi-led] coalition required to be faced,” the ruling said.

“Even if it could not be answered with reasonable confidence in respect of every incident of concern ... it is clear to us that it could properly be answered in respect of many such incidents, including most, if not all, of those which have featured prominently in argument. At least the attempt had to be made.”

Judges said the government “made no concluded assessments of whether the Saudi-led coalition had committed violations of international humanitarian law in the past, during the Yemen conflict, and made no attempt to do so”.

Video shows damaged buildings and homes in Yemen village hit by Saudi-led coalition airstrikes

They emphasised that the court was not ruling on the merits of arms sales to Saudi Arabia, but the lawfulness of how the government licences exports.

Judges found that although the UK had “engaged closely” with Riyadh in attempt to minimise civilian casualties in Yemen, that fell short of the legal obligation to assess the risk of war crimes.

Sir Terence said the ruling did not require the suspension of arms exports to Saudi Arabia but the government “must reconsider the matter” and estimate any future risks.

Andrew Smith, of Campaign Against Arms Trade, said: “We welcome this verdict, but it should never have taken a court case brought by campaigners to force the government to follow its own rules. The Saudi Arabian regime is one of the most brutal and repressive in the world, yet, for decades, it has been the largest buyer of UK-made arms.

“No matter what atrocities it has inflicted, the Saudi regime has been able to count on the uncritical political and military support of the UK.

“The bombing has created the worst humanitarian crisis in the world. UK arms companies have profited every step of the way. The arms sales must stop immediately.”

The government said it would be seeking permission to appeal the ruling, meaning the case could go to the Supreme Court.

“This judgement is not about whether the decisions themselves were right or wrong, but whether the process in reaching those decisions was correct,” a spokesperson added. “We disagree with the judgment.”

Labour MP Lloyd Russell-Moyle, who sits on the parliamentary committee for arms export controls, accused the government of “wasting time” by launching an appeal.

He called for a judge-led inquiry into wider arms sales, including to other countries involved in the Saudi-led coalition.

“I want a complete cessation of sales to Saudi Arabia and its partners,” he added, as campaigners celebrated outside the Royal Courts of Justice.

Demonstrators celebrate outside the Court of Appeal after winning their case (Reuters)

“The government must review all cases … this judgment is an indictment of the fact that MPs didn’t stop it sooner.”

The Department for International Trade is responsible for promoting military exports, the Export Control Organisation issues export licences, the Ministry of Defence offers technical advice and the Foreign Office considers the foreign-policy impact and human rights implications of sales.

Mr Russell-Moyle said Conservative leadership frontrunner Boris Johnson was foreign secretary in the period considered by the judgment, adding: “He signed off these licences and he should be held personally responsible.”

The call for a public inquiry was backed by Labour’s shadow foreign secretary, Emily Thornberry, who accused the government of “wilfully disregarding” evidence of Saudi war crimes. She said Labour would conduct root-and-branch reform of UK arms export rules.

Jeremy Corbyn called on the government to stop selling arms to Saudi Arabia immediately.

“UK advice, assistance and arms supplies to Saudi’s war in Yemen is a moral stain on our country,” the Labour leader wrote on Twitter. “Arms sales to Saudi must stop now.”

Saudi Arabia leads a coalition that has been conducting airstrikes in Yemen since 2015, in support of President Abedrabbo Mansour Hadi against Houthi rebels and other opponents. The UK has licensed nearly £5bn of arms exports to Saudi Arabia since the start of the Yemen war.

CAAT said thousands of people have been killed in Saudi-led bombing, and many more as a result of an ongoing humanitarian “catastrophe”, which includes a cholera outbreak and starvation.

Amnesty International, which intervened in the case, hailed the ruling as a “major step towards preventing further bloodshed”.

The international trade secretary defended the UK’s close relationship with Saudi Arabia, when questioned by MPs. He said the country was an important intelligence source and “a valuable partner in our shared combat against global terrorism and has helped keep numerous UK citizens safe”.

Conservative Julian Lewis said that since the 9/11 attacks, which were carried out by mainly Saudi terrorists, it had “become harder and harder to justify the closeness of our relationship” with the Gulf state.

Yemeni men inspect the damage at a factory allegedly targeted by Saudi airstrikes (AFP/Getty)

Fellow Tory Andrew Mitchell accused British and Saudi authorities of “marking their own homework” on war crime allegations.

Barry Gardiner, Labour’s shadow international trade secretary, said the case was a “damning indictment of the government’s handling of arms export licences to Saudi Arabia”.

“The [suspension of licences] is not enough,” he told the Commons. “We believe there should be an independent investigation into the Yemen conflict and it is shameful that the government should seek to appeal today’s judgment.”

Mr Gardiner warned that open weapons licences could be used to “bypass” the freeze, but Mr Fox denied that this would happen.

The court’s ruling came a day after a UN investigation found there was “credible evidence” to investigate Saudi crown prince, Mohammed bin Salman, over the murder of journalist Jamal Khashoggi.

Jo Swinson, the Liberal Democrat foreign affairs spokesperson, said the situation “cannot continue”.

“Saudi Arabia is an enemy of British values, including human rights and the rule of law,” she added.

“Their repeated violation and disregard for human rights should have ruled them out as an arms trading partner long ago.

“This court ruling is monumental. It is now clear for all to see: the UK arms sales to the Saudi regime are unlawful.”