Since King Salman became ruler of Saudi Arabia a couple of years ago at the age of 79, his favourite son, the impetuous Prince Mohammed bin Salman, has been unofficially running the country. Just to confuse things, though, an announcement from Riyadh yesterday means the prince is officially NOT running the country.

Mohammed bin Salman – or "MBS" for short – was formally appointed as Crown Prince which, despite any appearances to the contrary, means he is subordinate to his father. However, it was a step up from MBS's previous position as Deputy Crown Prince, minister of defence, economic supremo, etc, etc, and in practice it probably means he'll behave even more like a king than before.

Eager to show off his dynamism (a characteristic not usually associated with Saudi royals) and while still only Deputy Crown Prince, MBS plunged the kingdom into a fruitless war in Yemen and more recently, with the aid of Donald Trump and the Crown Prince of Abu Dhabi, has torn the Gulf Cooperation Council apart over a quarrel with Qatar. His promotion seems to be a reward for this.

In terms of palace politics, yesterday's elevation of MBS created a potentially tricky situation because it downgraded the previous Crown Prince, Mohammed bin Nayef, who is from a different branch of the royal family. The latter publicly signalled his acceptance of this decision by pledging allegiance to MBS. To ensure nobody was in any doubt about his loyalty, a photo was circulated showing the old Crown Prince and the new Crown Prince kissing hands.

Since then, others have been rushing to pledge their allegiance too – including the king of the fast food trade, McDonalds.

Viewed from outside, this seems a bit weird. Pledging allegiance to a ruling monarch is one thing but, historically speaking, pledging allegiance to someone who is not the monarch but has eyes on the throne can be a dangerous thing to do. Heads have rolled for less.

In theory, Arab monarchs rule by consent from their subjects, even if consent is little more than a formality and those giving the consent are a tiny section of the public. To formally take office a new ruler must receive the bay’ah – pledge of allegiance – from leading personalities. 

Saudi Arabia's Basic Law says: “Citizens are to pay allegiance to the king in accordance with the holy Qur’an and the tradition of the Prophet, in submission and obedience, in times of ease and difficulty, fortune and adversity.”  (It says nothing about allegiance to crown princes.)

In the case of a new king, the “citizens” making the pledge are, in order of precedence, other members of the Saudi royal family, the ulema (religious scholars), the council of ministers and the quasi-parliament, the consultative council. Others who wish to get in on the act but are in no position to give a formal bay'ah have to look for alternative methods – which is where newspaper adverts come in handy. 

Posting on Twitter, Reuters journalist Stephen Kalin observes that local newspapers are now full of ads pledging allegiance – including one from the McDonalds burger chain (above). McDonalds, it should be noted, has been careful not to exclude the king from its tribute to the new Crown Prince.

While businesses may see this as a convenient way of buttering-up the royals and getting some publicity for themselves at the same time, it also raises doubts about the loyalty of rival firms which have not advertised. 

Stand by for further royal tributes from Burger King, KFC, Pizza Hut and thousands of kebab stalls.