Welcomed at the Cairo Coptic Cathedral, Bin Salman met with Pope Tawadros II along with the Deputy Prime Minister and Minister of Defense as part of a three-day visit to Egypt to discuss bilateral ties between Egypt and Saudi Arabia.
Organised by Stop The War Coalition and Hands Off Yemen, hundreds of demonstrators stood outside Downing Street holding placards that read "Crown Prince not welcome".
May's Conservative government said Mohammed's visit would strengthen co-operation in "tackling global challenges such as terrorism, extremism, the conflict and humanitarian crisis in Yemen and other regional issues".
Saudi Arabia, the UAE, Egypt and Bahrain cut diplomatic and trade links with Qatar last June, suspending air and shipping routes with the world's biggest exporter of liquefied natural gas, which is home to the region's biggest USA military base.
Mr Corbyn said a "humanitarian disaster" was taking place in Yemen as a result of the bombing campaign and a Saudi blockade of Yemeni ports.
Garry, a 35-year-old teacher who declined to give his last name, agreed.
The crown prince will head to Chequers for talks and a private dinner with the PM today, that will focus on foreign policy issues, including Yemen and Iran.
Labour MP Chris Williamson, who was in attendance at the protest, echoed the feelings of protesters during a speech.
During the meeting, Archbishop Welby raised concerns about the limits placed on Christian worship in Saudi Arabia, "and highlighted the importance for leaders of all faiths to support freedom of religion or belief, drawing on the experience of the UK". And because we know that Saudi Arabia isn't big on feminism, it is notable that young women there are going big on technology and are keen to embrace online shopping. All foreign dignitaries are invited to meet the Queen and other members of the Royal Family during state visits.
It's also prompted comparisons to the official welcome offered to US President Donald Trump that he has not yet been taken up and is set to be downgraded to a "working visit" in light of expected protests when he enters the UK. The kingdom faces wide worldwide criticism for its airstrikes killing civilians and striking markets, hospitals and other civilian targets.
Since the Saudi-led military intervention started in Yemen in March 2015, the Arab world's poorest country has found itself on the brink of a devastating humanitarian crisis, with at least 10,000 people killed.
The U.K. has been an historic arms supplier to Saudi Arabia, gaining lucrative deals that number in the billions.
"Anyone concerned about human rights and freedom of speech will expect the United Kingdom government to ensure that that message gets through to Crown Prince Salman loud and clear".