Senior politicians have called for an urgent independent investigation into reports of breaches of international humanitarian law on both sides of the conflict in Yemen.
Speaking in the House of Commons on Thursday, Stephen Twigg, chair of the international development committee, said it was "remarkable" that Saudi Arabia, which is leading coalition airstrikes intervening in the Yemen conflict, was also taking the lead in investigating alleged war crimes.
The coalition has faced a series of accusations of human rights breaches since the start of the conflict as the number of civilians killed in coalition airstrikes rises.
Twigg said: "I find it remarkable that the government still holds the line Saudi Arabia must take responsibility for investigating its own alleged violation."
The UK government has repeatedly been questioned by ministers over the past 14 months about Saudi Arabia’s investigations, Twigg continued. "At what point will the British government take the view we need to move to an independent inquiry?"
The debate comes just days after the release of Foreign Office documents that showed the British military has provided training to a Saudi war crimes investigations unit headed by a Bahraini judge campaigners claim is partisan.
Human rights campaigners said Britain's role in training the Joint Incident Assessment Team (JIAT), a Saudi-led coalition military body set up in May 2016, had made the UK complicit in whitewashing human rights abuses in the Gulf.
The Ministry of Defence (MoD) was found to have delivered two training sessions for JIAT on the process of investigating alleged violations of international humanitarian laws, documents released through a freedom of information request revealed.
The Foreign Office response added the MoD had not been directly involved in actual investigations, although the embassy in Riyadh keeps "regular contact" with JIAT.
Human rights campaigners further questioned the credibility of the UK-trained investigative body overseen by Mansour al-Mansour, a Bahraini judge who presided over the military court trials of some 300 civilians during the Kingdom's crackdown on Arab Spring protests in 2011.
Sayed Ahmed Alwadaei, the director of advocacy at the Bahrain Institute for Rights and Democracy, said: "It is farcical that the judge who condemned torture victims to life imprisonment in Bahrain is now in charge of investigating the murder of civilians in Yemen. With al-Mansour, the UK has trained a serial violator of human rights to investigate violations of humanitarian law."
Tom Brake, Lib Dem MP for Carshalton and Wallington, said in a statement before the debate: "The credibility of the JIAT depends on the credibility of its members.
"Mansour al-Mansour, a member of JIAT, had played a central role in the trials of Bahraini democracy protesters, in a judicial process which, according to a commission of inquiry ‘overtook the national system of justice. A pattern of due process violations occurred at the pretrial and trial levels that denied most defendants elementary fair trial guarantees.'"
"How can he be qualified to adjudicate on civilian casualties in Yemen?” Brake added.
During the Commons debate, Alistair Burt, the Conservative MP for North East Bedfordshire, said it was in the interests of stability in the region for Britain to support its allies.
He added: "Saudi Arabia is directly affected by instability in Yemen. Firstly it can be and has been physically attacked between 2015 and 2016; some 37 ballistic missiles were fired by Houthi rebels, inflicting damage to Saudi Arabia. It’s important this is known."
The Foreign and Commonwealth Office told BuzzFeed News: “The Government is not opposing calls for an international independent investigation but, first and foremost, we want to see the Saudis investigate allegations of breaches of international humanitarian law (IHL) which are attributed to them; and for their investigations to be thorough and conclusive. This is the standard we set ourselves and our allies.”
At least 10,000 people have been killed in Yemen’s 18-month civil war, according to the United Nations. In the summer, the UN's human rights office said nearly 4,000 civilians had been killed in the conflict, with airstrikes by the Saudi-led coalition responsible for some 60% of deaths. Amnesty has branded the situation in Yemen the “forgotten war”.
Saudi Arabia is leading coalition airstrikes intervening in Yemen’s civil war on behalf of President Abd-Rabbu Mansour Hadi against Houthi militia and supporters of the exiled President Hadi.
As a result, Britain's arms deal with the Kingdom has been under increased scrutiny. Last month the government admitted Saudi Arabia had used B-755 cluster munitions supplied by the UK in an attack on northern Yemen in January 2016. It prompted Saudi Arabia to pledge not to use them in its military operations.
Andrew Smith, of Campaign Against Arms Trade, which claims the UK has licensed £3.3 billion worth of arms to the regime since Saudi Arabia began bombing Yemen last March, said: "The UK government has been complicit in the destruction of Yemen and the humanitarian catastrophe that has been forced upon the Yemeni people.
"Parliament must stand with those caught in the middle of the devastating conflict and support an international investigation into the human rights abuses that are taking place."