Campaigners have won a legal challenge at the Court of Appeal over the UK government’s decision to allow arms sales to Saudi Arabia.
Campaign Against Arms Trade (CAAT) argued the decision to continue to license military equipment for export to the Gulf state was unlawful.
It said there was a clear risk the arms might be used in a serious violation of international humanitarian law.
Judges said licences should be reviewed but would not be immediately suspended.
Giving judgment in London, Master of the Rolls Sir Terence Etherton said the government “must reconsider the matter” and estimate any future risks.
Equipment sold to Saudi Arabia includes Typhoon and Tornado fighter jets, as well as precision-guided bombs.
The sales contribute to thousands of engineering jobs in the UK, and have provided billions of pounds of revenue for the British arms trade.
Andrew Smith, of CAAT, welcomed the judgment, saying the Saudi Arabian regime was one of the most brutal and repressive in the world yet for decades had 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,” he said.
“The bombing has created the worst humanitarian crisis in the world.”
There has been much public debate about the supply of weapons to Saudi Arabia, particularly in light of the Saudi involvement in the conflict in Yemen.
Research by the Stockholm International Peace Research Institute, a think tank which monitors the global weapons industry, puts Britain in second place as a supplier of “major arms” to Saudi Arabia, behind the United States and ahead of France.
Saudi Arabia’s total imports of major arms more than tripled in the period from 2012 to 2017 compared with the previous five years.