Jeremy Corbyn said on Tuesday that Theresa May, the prime minister, should announce to Crown Prince Mohammad bin Salman, 32, on Wednesday that the UK would no longer supply arms to Riyadh “while the devastating Saudi-led bombing of Yemen continues”.
May should also “make clear Britain’s strong opposition to widespread human and civil rights abuses in Saudi Arabia”, he said.
Anti-war and human rights groups plan a protest outside May’s Downing Street office on Wednesday.
Mohammad bin Salman is scheduled to have talks with May, as well as a rare audience with Queen Elizabeth and dinner with Prince Charles after arriving from Egypt.
Boris Johnson, British foreign minister, lauded security ties with “one of Britain’s oldest friends in the region” in a newspaper article last week and praised bin Salman’s reforms.
The recently introduced changes are ostensibly aimed at reducing his country’s reliance on oil, tackling chronic corruption and transforming the kingdom.
But rights groups and opposition legislators have criticised Britain’s support for bin Salman, particularly over the licensing of about $6.37bn worth of arms sales to Saudi Arabia since the start of the Yemen conflict.
A coalition assembled by Saudi Arabia launched an air campaign against the rebels in March 2015 to try to restore the internationally recognised government of President Abd-Rabbu Mansour Hadi.
Since then, more than 10,000 people have been killed in the fighting, millions have been forced from their homes and the impoverished country has been pushed to the brink of famine.
Due to a crippling Saudi air and sea blockade on the country, more than three-quarters of the population – some 22 million people – need humanitarian assistance, while 11 million require dire help in order to survive.