Saudi Arabia’s new crown prince Mohammed bin Salman will arrive in London on 7 March for a three-day state visit during which he will meet with Prime Minister Theresa May, government officials and the royal family.

Foreign Secretary Boris Johnson wrote earlier this week that the young prince’s visit will see the UK and the Kingdom’s relationship “turn a new page”.

While MbS, as he is known, is bringing sorely needed social and economic reforms to the country, his ruthless tactics for dealing with critics and rivals – as well as his involvement in neighbouring Yemen’s civil war – have been widely criticised.

Who is the prince?

MbS, King Salman’s eldest son by his third wife, was appointed as crown prince in June last year.

Saudi Arabia king's golden escalator get stuck as he tries to descend from his plane in Russia

Among several other important roles, the 32-year-old is the country’s defence minister. He is widely understood to be the driving force behind the Kingdom’s forays into Yemen, where it backs the exiled government over the Iranian-supported Houthi rebels.

His rise has followed that of his father: King Salman ascended to the throne in January 2015 after the death of his half-brother Abdullah bin Abdul Aziz. MbS, previously in charge of his father’s royal court, has been rapidly promoted since then to various cabinet posts at the expense of those older or more experienced.

The appointment of such a young heir to the throne effectively sets the tone of Saudi policy for decades. He is by far the second most powerful person in the country – and some would argue more important than his ailing 81-year-old father.

Why is he so important?

MbS is also the locomotion behind Saudi Arabia’s ‘Vision 2030’, a hugely ambitious and wide-ranging blueprint to wean the country off dependence on oil following a global slump in prices.

Saudi Arabia struggles to employ its most-educated women Show all 4 1 /4 Saudi Arabia struggles to employ its most-educated women Saudi Arabia struggles to employ its most-educated women SAUDI WOMEN122.jpg SAUDI WOMEN: Tahany Omar, 36, has a Masters of Business Administration from the US but has found the job market challenging in Riyadh, Saudi Arabia; she works in an investment firm, but not in management. Washington Post photo by Linda Davidson Saudi Arabia struggles to employ its most-educated women SAUDI WOMEN124.jpg A young Saudi woman in her 20's shops for dresses on the women-only level at Kingdom Centre Mall in Riyadh, Saudi Arabia in October. Unless designated as a women's only area, most shopping in Saudi Arabia is staffed by men. Washington Post photo by Linda Davidson Saudi Arabia struggles to employ its most-educated women SAUDI WOMEN123.jpg Saudi men reflected in the mirrors of the Al-Faisaliyah Center viewing level which overlooks the expansive city of Riyadh, Saudi Arabia Washington Post photo by Linda Davidson Saudi Arabia struggles to employ its most-educated women SAUDI WOMEN121.jpg SAUDI WOMEN: Zainab Al Talib, left, assists legal consultant Tala Al-Hejailan at the law offices of DLA Piper in Riyadh, Saudi Arabia on October 8. Hejailan is a lawyer, but cannot practise law in Saudi Arabia, which will not grant licences to women. Washington Post photo by Linda Davidson

Huge societal change has quickly arrived in the very conservative country as a result of his appointment: women are being allowed to drive and it is hoped will make up 30 per cent of the workforce over the next 12 years. MbS has even publicly criticised the Kingdom’s religious establishment as out of touch with the times and promised a return to more “moderate Islam”.

Many Saudis have embraced the long overdue social reforms. They worry, however, that the economic forecast still looks bleak for normal households – and the reforms serve as a smokescreen for more oppressive measures.

The arrest of more than 300 business leaders, royals and politicians in an anti-corruption crackdown last November was widely interpreted as a clampdown on political freedoms and other forms of dissent.

The humanitarian crisis in Yemen – where eight million people are on the brink of famine – is an ongoing international concern. The situation is now so dire it is being referred to as “Saudi’s Vietnam”.

What is the purpose of the UK visit?

As the foreign secretary has pointed out, British exports to the country have risen to £6.2bn – a 41 per cent increase since 2010.

Most of that is arms sales, including advanced munitions and Typhoon jets, which rights groups say are destined for use in Yemen’s devastating conflict.

Ministers also hope Riyadh will pick London for the planned stock market flotation of Aramco, the state oil group.

British government sources have stressed that Saudi Arabia is also a key intelligence and anti-terror ally for Western governments.

“The partnership between the UK and Saudi Arabia already helps make both of our countries safer through intelligence sharing, which has saved British lives, and more prosperous, with thousands of jobs created in the UK and substantial opportunities for British companies in Saudi Arabia,” Theresa May said in a statement. “The visit of the crown prince will establish the platform for that relationship to become even stronger.”

Why are people protesting?

About Saudi Arabia’s still dismal human rights record, its involvement in the three-year-old Yemeni war, and the UK government’s arms sales to the country.

The Saudi authorities leading a bombing campaign to restore Yemen’s government have been repeatedly accused by the UN and rights groups of failing to take adequate precautions to avoid loss of civilian life.

The Stop the War coalition and Campaign Against the Arms Trade (CAAT) are calling for pickets outside Downing Street during all three days of MbS’s visit, which are expected to attract large numbers of protesters.

“The UK has armed and supported the terrible war since day one, and there is no doubt that arms sales will be top of the agenda next week,” a statement from CAAT’s Andrew Smith said.

“Theresa May is putting the interests of arms dealers above the rights of Yemeni people.”