All sales of UK weapons which could be used in Saudi Arabia's military action in Yemen should be halted until the completion of an independent inquiry into alleged breaches of human rights, a parliamentary report has said.
The joint report by the House of Commons Business and International Development Committees said it had been presented with evidence of "clear violations" of international humanitarian law (IHL) including the death of 47 civilians - among them 21 women and 15 children - and injuries to 58 more when a house hosting a wedding party was struck by two missiles fired by military aircraft.
But the publication exposed deep differences between MPs on the issue, as the Commons Foreign Affairs Committee released its own rival report insisting that exports should be blocked only if the UK courts rule the weapons sales unlawful.
The highly unusual decision to publish two simultaneous reports is a mark of the depth of controversy over claims that UK-made armaments are being used in indiscriminate bombing raids on civilian targets by the Saudi-led coalition fighting Shia rebels known as the Houthis in Yemen.
International medical aid charity Medecins Sans Frontieres has accused the coalition of war crimes for an air strike on its hospital which killed at least 11 last month.
An internal investigation launched by Saudi Arabia is regarded as inadequate by campaigners, including the Campaign Against Arms Trade (CAAT), which is taking legal action to seek the suspension of arms export licences to the country.
The FAC's Conservative chairman Crispin Blunt is understood to have drawn up the rival document after objecting to proposals to issue the call for immediate suspension under the banner of the House of Commons Committees on Arms Export Controls (CAEC) - a panel which brings together the cross-party committees for Business, Foreign Affairs, Defence and International Development.
Reports suggested that Mr Blunt walked out of a private meeting of CAEC to prevent a vote being taken on the draft report, which he regarded as one-sided. Meanwhile, the Defence Committee has given no indication of whether it intends to publish its own report.
Conservative MP Chris White, who chaired the CAEC inquiry into the exports and is a member of the Business Committee, said: "The UK led the way in establishing international humanitarian law to govern the sale of arms. The conflict in Yemen has raised serious concerns that we are not showing equal determination in ensuring that these are respected.
"During this inquiry we have heard evidence from respected sources that weapons made in the UK have been used in contravention of International Humanitarian Law. The Government can no longer wait and see and must now take urgent action, halting the sale of arms to the Saudi-led coalition until we can be sure that there is no risk of violation.
"We call on the Government to continue the UK's long-standing commitment to IHL and lead the international community in establishing a strong, independent inquiry. The circumstances surrounding incidents in Yemen, such as allegations of the use of cluster bombs, must be firmly established and send a clear message to all combatants in Yemen that human rights must be respected.
"The current system for overseeing the sale of arms must be improved. At present we do not have sufficient transparency to hold licensing decisions to account or the confidence that the benchmarks ensuring human rights law is respected are high enough. This must be addressed immediately."
Labour MP Stephen Twigg, chair of the International Development Committee, added: "We remain unconvinced that Saudi Arabia is best placed to investigate reports of breaches of humanitarian law – progress so far has been too slow.
"It is important to remember that both sides to the conflict are potentially involved in breaches of humanitarian law and without credible investigations, neither side is being held accountable for their actions."
Arms trade law made clear that export licences should not be granted "where there is a clear risk that they might be used in a serious violation of IHL", said Mr Twigg, adding: "It is hard to understand how a reliable licence assessment process would not have concluded that there is a clear risk of misuse of at least some arms exports to Saudi Arabia."
The FAC report backed an independent UN-led investigation into allegations of human rights violations, but said that the courts are the most appropriate body to decide whether the Government has broken the law by permitting continued sales.
"Saudi Arabia is a key partner of the United Kingdom in addressing our shared challenges in the Middle East," said Mr Blunt.
"I am yet to hear any persuasive argument for how we better secure our many strategic objectives in the region without a strong relationship with Saudi Arabia.
"This includes bringing about a political solution to the current conflict in Yemen, that was so deplorably precipitated by the armed Houthi rebellion in 2014.
"However, the massive British interest in continued UK-Saudi relations cannot override our wider legal and moral obligations.
"It is crucial that the UK does everything in its power to ensure full compliance with international humanitarian law by the Saudi-led coalition."
Mr Blunt said there was "a clear need for a wider discussion" on the suitability of the laws governing arms exports.
Andrew Smith, of Campaign Against Arms Trade, said the FAC's recommendations would mean any suspension of arms sales being delayed for at least four months and warned that the judicial review should not be used as an excuse for inaction.
"It should not take a court case for the UK to stop arming one of the most repressive dictatorships in the world while it is creating a humanitarian catastrophe in Yemen, one of the poorest countries," said Mr Smith.
"The evidence that Saudi Arabia is violating international humanitarian law is overwhelming, and our legal action cannot be used as an excuse to carry on with business as usual."
Welcoming the tougher report from the Business and International Development committees, Mr Smith said: "The report is definitely to be welcomed, although it should not have taken 18 months since the bombing began for arms sales to be scrutinised in this way.
"The humanitarian catastrophe in Yemen has only got worse, and the Government's response has been to sell even more weapons. The UK has been complicit in the destruction; now it must act to stop it. That means ending the arms sales and ending its uncritical support for the Saudi regime."
Amnesty International UK's arms control director Oliver Sprague said: "This 'war of the reports' shouldn't become a distraction from the very simple fact that the UK is arming Saudi Arabia while the Saudi-led coalition is behind wave after wave of indiscriminate bombing in Yemen.
"Thousands of Yemeni civilians have already been killed and injured in devastating Saudi-led airstrikes on hospitals, schools and homes - what clearer demonstration of the risk of sending more arms to Saudi Arabia does the Government need?"