Members of Congress have also heavily criticised Saudi Arabia's human rights record over its role in the Yemen conflict and the murder of Saudi journalist Jamal Khashoggi in Istanbul last October.
Shortly after the ruling, Fox made an emergency statement to the Commons and confirmed that the government would seek to appeal.
The court ruled that the United Kingdom government "must reconsider the matter" and weigh up future risks.
"We disagree with the judgment and will be seeking permission to appeal".
Britain is the world's sixth largest seller of arms, after the United States, Russia, France, Germany and China, according to the Stockholm International Peace Research Institute (SIPRI).
Shares in Britain's BAE Systems defence and aerospace giants lost nearly 3% of their value within an hour of the government's announcement.
Thursday's decision was part of a long-running court battle that the UK-based Campaign Against Arms Trade non-profit group first launched against the British government in December 2015.
Britain accounts for 23% of arms imports to Saudi Arabia and previous year signed a multi-billion-pound preliminary order with Riyadh for 48 Eurofighter Typhoon fighter jets.
U.S. Special Representative for Iran Brian Hook met Saudi Arabia's Deputy Defense Minister Prince Khalid bin Salman in Riyadh on Friday, the minister tweeted.
When it comes to the Saudi-led war in Yemen, "it is our bombs that are dropping on those civilians".
Al-Jubeir, in his London meet, said that the global community is determined to push back against "aggressive" behavior of Iran, adding that Saudi Arabia does not want war with Iran.
Latest figures estimate that the death toll in the complex civil war in Yemen since 2016 is fast approaching 100,000 - although there is now a ceasefire - with almost 11,700 civilians killed in attacks that have directly targeted them.
"It does mean that the United Kingdom government must reconsider the matter, must make the necessary assessments about past episodes of concern, allowing for the fact that, in some cases, it will not be possible to reach a conclusion".
"Saudi Arabia serves as a bulwark against the malign activities of Iran and its proxies", the White House said, adding that the resolutions would affect the ability of American partners "to deter and defend against Iran's hostile acts".
"UK advice, assistance and arms supplies to Saudi's war in Yemen is a moral stain on our country", Labour leader Jeremy Corbyn said. "The arms sales must stop immediately". "Our whole assessment has been infused with IHL (international humanitarian law) considerations, indeed everything was looked at through the prism of IHL", he said.