A campaign group has launched a courtroom battle against the United Kingdom’s arms sales to Saudi Arabia, warning the weapons are worsening a major humanitarian disaster in war-torn Yemen.

The United Kingdom’s High Court on Tuesday began hearing the case brought forward by the Campaign Against Arms Trade (CAAT), which says arms exports have contributed to the deaths of thousands of civilians.

The UK-based group is challenging the lawfulness of a decision taken by the British government in 2020 to continue supplying weapons to the Saudi-led coalition involved in the nine-year-old conflict in Yemen.

It marks the latest development in a long-running battle over the legality of the exports, which CAAT says have made the UK more than 23 billion pounds ($28bn) since the war began.

CAAT won a similar fight in 2019, when Court of Appeal judges said continuing to license military equipment that could be used in the war in Yemen for export was unlawful amid concerns it may have been used to commit war crimes.

The government temporarily halted sales following the ruling. UK law does not allow for the export of weapons if there is a “clear risk” they may be used to carry out war crimes.

However, exports resumed in mid-2020 under the order of then-trade minister Liz Truss after a governmental review.

The review concluded that possible violations of international humanitarian law by actors using UK-supplied weapons were only “isolated incidents”.

Governmental review under scrutiny

British arms sales to Saudi Arabia have continued in recent years, despite the UK’s leading ally, the United States adopting a partial ban on weapons exports to the kingdom because of the war in Yemen.

Meanwhile, campaigners and rights groups have disputed the validity of the governmental review’s findings.

“The ample evidence of laws of war violations by the Saudi-led coalition in Yemen throughout the war make clear that these violations are not simply ‘isolated incidents’ as claimed by the UK government,” Niku Jafarnia, Yemen and Bahrain researcher at Human Rights Watch, said.

“UK weapons have been used in some of these violations with total impunity,” Jafarnia said.

“At a time when the UK is promoting a rules-based international order, and rightly calling out Russia for serious violations of international law, it needs to apply those same rules to itself and end the sale of weapons to Saudi Arabia.”

The weapons supplied by the UK include Paveway guided bombs and Brimstone and Storm Shadow missiles.

‘UK bombs kill civilians’

Emily Apple, a spokesperson for CAAT, accused the government of “caring more about profit than war crimes”.

“The … case is being taken in solidarity with the people of Yemen who deserve justice,” Apple said.

“We cannot sit by while UK bombs kill civilians and cause devastation while UK arms dealers profit.”

The conflict in Yemen started in 2014 when Houthi rebels, backed by Iran, seized large swaths of the country, including the capital, Sanaa.

The war escalated in March 2015, when the Saudi Arabia-led coalition intervened in an attempt to restore the government of President Abd-Rabbu Mansour Hadi.

The coalition has been assisted by several Western powers, including the UK and the US.

Both sides in the conflict have since been accused of war crimes during fighting that has killed more than 8,900 people to date, according to the Yemen Data Project.

A United Nations-brokered truce deal agreed to in April of last year has largely held, despite expiring in early October.

The agreement has delivered the longest stretch of relative calm in Yemen since the war began, but both sides have stepped up moves to economically weaken the other in the interim.