Among those caught in the unprecedented arrests this week of top princes, wealthy businessmen and senior officials was the scion of one of Saudi Arabia's most recognisable families - Bakr bin Laden - chairman of the kingdom's pre-eminent contractor and Osama bin Laden's half-brother.

It was a stunning end to a decades-old alliance between the ruling Al Saud and Binladin families that saw the Saudi Binladin Group secure a near-monopoly on mega-expansion projects in Islam's two holiest sites, Mecca and Medina, throughout the reigns of successive Saudi monarchs.

The government says 201 people have been taken into custody in the purge, which comes amid an anti-corruption probe it says uncovered at least USD 100 billion in graft and embezzlement. Saudi critics and experts have called the arrests a bold and risky move by Crown Prince Mohammed bin Salman aimed at consolidating power as he sidelines potential rivals, silences critics and dismantles alliances built with other branches of the royal family. The 32-year-old crown prince, who is the son of King Salman and popularly known by his initials MBS, is leading the anti-corruption investigation.

He's also the force behind the so-called Vision 2030 plan, a blueprint for how to restructure the country and wean it from its dependence on oil revenue. The arrests of Bin laden and the others not only signal the end of old alliances, but also speak to the larger demands being made on the business community to pay into the crown prince's economic vision in an era of lower oil prices.