The court ruled that the decision not to suspend or cancel arms sales to Saudi Arabia was "irrational or unlawful."
Following the announcement, the Amnesty International, which was acting as an intervenor in the case, called the decision a potentially deadly setback to Yemeni civilians.
"This is a deeply disappointing outcome which gives a green light to the UK authorities – and potentially Saudi Arabia’s other arms suppliers – to continue authorizing arms transfers to the Kingdom despite the clear risk they will be used to commit violations," Head of Arms Control and Human Rights James Lynch said.
The UK government has been blamed by humanitarian organizations, like the Amnesty International and Human Rights Watch for fueling the Yemeni conflict by supplying Saudi Arabia with arms. In late 2016, a parliamentary report urged for the suspension arms sales and accused the government of willfully ignoring their misuse.