The prince is guilty of murder. That was the verdict rendered against the Saudi prince, Saud Abdulaziz bin Nasser Al Saud, regarding the death of his servant, Bandar Abdulaziz. It is a victory for the people of Saudi Arabia who, for the first time in their lives, can see a "blueblood" royal held accountable for his actions against a commoner.

His trial at the Old Bailey sent a strong message that a Saudi prince and a pauper are the same in the eyes of the law in Britain, and that British justice is superior to the Saudi court system, which claims to uphold Islamic standards.

Many Saudis are cheering the verdict: they know that if this murder had occurred in Saudi Arabia, the killer would not have seen a single day in prison. The victim in this case had no hopes of receiving justice in his homeland, but the British court has upheld the fundamental principle of equality under law.

Millions of people in Saudi Arabia were watching the trial closely, and the outcome gives them hope that the impartial rules of western jurisprudence may one day be emulated in their land. In Saudi Arabia and other despotic regimes, where people are divided into rulers and subjects, the judicial system is guided by the whims of the ruling family and the accused prince would have been given a free pass. This may have been on the mind of detective chief inspector John McFarlane, who summarised the situation: "This verdict clearly shows no one, regardless of their position, is above the law."

The convicted prince is a "Royal Highness" prince – one of the few hundred males eligible by birth to ascend to the Saudi throne. There are two classes of Saudi princes. Male descendents of King Abdulaziz, the founder of Saudi Arabia, are given the title of "Royal Highness", while other princely males have to make do with a mere "Your Highness". It is worth noting that these titles are an anathema to Islam's egalitarian tradition and, in fact, have no foundation in Arab history. They were imported to Saudi Arabia from the United Kingdom in the 1940s.

Bandar Abdulaziz, the prince's victim, was a black man who grew up in a government orphanage with no known parents – the worst possible combination in Saudi Arabia in terms of social worth. In the eyes of many royals, Bandar was just a slave – and it's a view that the Saudi courts usually share.

Take the case of Sulaiman al-Huraisi, 28, a black man who was beaten to death at his house in Riyadh by members of the Saudi religious police. Huraisi had been kicked in the head by 10 members of the government militia (which was later cleared of responsibility for his death).

That was not an isolated incident. It reflects the policy of the Saudi monarchy, which bars black people from becoming judges and holding senior military posts. In addition, black women are not allowed to work as on-camera reporters for Saudi state television stations, a former reporter told me. "We can only use your voice," her manager told her.

Bandar was one of thousands of black Saudis who are modern-day slaves of the ruling family, serving them in any capacity, including sexually. The culture of slavery pervades the country and while slavery was officially banned in 1964, it continued in practice, especially inside the walls of thousands of princely palaces.

Members of the princes' inner circle are popularly called khawee, "minion". Essentially, they are subordinates who are there for the service or the amusement of a prince with an inflated sense of self-importance. A khawee could, for example, be an Arab writer who realises that being a member of the inner circle of a Saudi prince is extremely rewarding.

Abusing subjects is nothing new to the Saudi royals, who are driven by a sense of entitlement and impunity, even outside their kingdom's borders. In the past few years, at least three princesses have been accused of physically abusing their maids in the United States. In one case, the princess agreed to pay a $1,000 fine, though without making any admission of guilt.

In 2003, Fahd bin Nayef bin Saud bin Abdulaziz Al Saud, a second cousin of the convicted prince, murdered a teenage Saudi boy, Monther al-Qadi, by shooting him with his personal machine gun in broad daylight in the streets of Riyadh. After a few crafty manoeuvres by Prince Salman, governor of Riyadh, the case ended in a dramatic fashion in May 2004. Minutes before the prince was to be executed, Monther's father pardoned the killer.

The Saudi ruling family is not all that different from other ruling families in the Middle East, who can pretty much walk all over the law in their Gucci loafers. The major reason for these abuses is the absolute power that the Al Saud family wields without challenge, acting as if they are above the law that they control.

In previous cases the Saudi regime has pressured western governments not to take action against members of the royal family. A British inquiry into corruption allegations related to arms sales was halted after the Saudis threatened to stop co-operating with Britain on counterterrorism.

France also received strong Saudi threats to cancel billions of dollars in contracts if Prince Nayef al-Shaalan, who is not an Al Saud but is married to the king's niece, was tried for smuggling two tons of cocaine. A French court nevertheless convicted him in absentia and sentenced him to 10 years.

Prince Saud's conviction gives all of us some hope that one day our people will enjoy a modern court system that sees no difference between a prince and a pauper. I am hoping that Britain might export its brand of justice to our country to help modernise our medieval judiciary. That is undeniably a better and more useful export to our people than any sales of fighter planes.