Labour's leader demanded Britain stop selling weapons to the powerful Arab state to halt a "humanitarian disaster" in Yemen.
And he declared: "British military advisors are directing the war."
Crown Prince Mohammed bin Salman will face angry protests today as he arrives at Downing Street for a three-day trip to Britain.
Challenged over the regime's record on women's rights and the blockade of Yemen, Theresa May said "we are all concerned" about the "appalling" situation.
Comment: If she was so concerned then why are they selling them billions in arms? Shameless: UK sells 457% more arms to Saudi Arabia since it started bombing Yemen
Yet she strongly defended the visit at Prime Minister's Questions.
She told Mr Corbyn: "The link that we have with Saudi Arabia is historic, it is an important one and it has saved the lives of potentially hundreds of people in this country.
Comment: Saudi Arabia wouldn't exist were it not for the UK:
- How British Zionism created both the Kingdom of Saudi Arabia and Israel
- You can't understand ISIS if you don't know the history of Wahhabism in Saudi Arabia
"I welcome the fact that the Crown Prince will be sitting down with, as the guest of, a female Prime Minister."

"Millions face starvation. 600,000 children have cholera because of the Saudi-led bombing campaign and blockade.

"British military advisors are directing the war.
"It cannot be right that her government is colluding in what the United Nations says is evidence of war crimes.
"Will the Prime Minister use her meeting today with the Crown Prince to halt the arms supplies and demand an immediate ceasefire in Yemen?"
Mr Corbyn also accused the government of continuing to "suppress" a report into the funding of extremism.
"[It] allegedly found evidence of Saudi funding going to terrorist groups here in the UK, thus threatening our security," he said.
"When will that report come out?"
Mohammed bin Salman's trip is set to be dominated by protests over the kingdom's involvement in the Yemen civil war as well as human rights abuses in his own country.
The Crown Prince will be received by the Queen at Buckingham Palace at the start of a trip that is set to be dominated by protests over his country's role in the bloody civil war in Yemen.
Yemen has been embroiled in a bloody civil war since 2014 when rebels took over the capital city of Sanaa.
Saudi Arabia is the main player in a coalition supporting the Yemeni government against the Houthis in a war which has caused a humanitarian catastrophe.
SNP MP Stewart McDonald also challenged Mrs May to stand in the House of Commons and declare that jailed blogger Raif Badawi "is no criminal and should be set free".
Downing Street previously said Mrs May will raise "deep concerns" over the humanitarian crisis in Yemen during the visit.
But the Prime Minister would not guarantee she would raise Badawi's case this time.
Human rights campaigners are planning to stage a protest outside Downing Street at 5pm.
According to analysis by human rights charity Reprieve, executions have doubled under the Crown Prince despite social reforms like allowing women to drive and attend sports matches.
The organisation said since his appointment in July 2017, 133 people had been executed compared with 67 in the previous eight months.
Amnesty International said reforms in Saudi Arabia were "largely a mirage", with "peaceful critics" of the government thrown in jail and women reliant on permission from men if they want to travel, be educated or get a job.
UK director Kate Allen said: "We'd like to see Theresa May finally showing some backbone."
Rob Williams, chief executive at War Child UK, added: "Britain is complicit in the humanitarian crisis in Yemen through providing diplomatic support to Saudi Arabia.
"As well as selling our most high tech and deadly weapons to a coalition that the United Nations has verified as committing grave violations against children."
Mrs May turned the tables on Labour - saying Shadow Foreign Secretary had said "the UK can sell arms to any country as long as they're used within the law" just hours before PMQs .
She added she had raised concerns about the Saudi blockades of ports in Yemen during a meeting in December and it withdrew.
She said: "This vindicates the engagement that we have with Saudi Arabia, to be able to sit down with them.
"Their involvement in Yemen came at the request of the legitimate government of the Yemen, it is backed by the United Nations Security Council and as such we support it."






Comment:
For an idea of the Saudi influence in British politics:
See also: