For those who had not been paying attention to the rise of Saudi Arabia’s Crown Prince Mohammed bin Salman, his recent dramatic detention of fellow princes and other senior figures over corruption allegations came out of the blue. But amid some pretty tough competition for the world’s attention — a quasi-coup in Zimbabwe, more Brexit tumult — he has kept up the momentum ever since. On Thursday it emerged that the Saudi authorities were seeking vast sums — up to $300bn — in exchange for dropping charges relating to the alleged $100bn corruption racket. It is against that background that two people close to the situation confirm the existence of deepening but secret talks between the Saudis and the Swiss banking sector. Precise information about the whys and wherefores is scant. But there are several plausible reasons for the contact.

The most obvious relates directly to the corruption probe. As Prince Mohammed, or MbS as he is widely known, consolidates his power base, he is keen to ensure those he seeks to weaken cannot skirt his crackdown through offshore routes. If MbS is indeed asking the Swiss banks for information on Saudi clients, it is far from certain that the pitch could succeed. Recommended Opinion: Oil market’s new political reality after Saudi Arabia arrests Activist fund pushes Credit Suisse chief on cost-cuts Saudi Arabia crackdown and persistence of the unforeseen

The US authorities did strong-arm Swiss banks into handing over client information — and extracted $5.5bn in penalties and compensation over the affair — but only because clients had breached US tax rules requiring the disclosure of offshore accounts. Saudi Arabia, which levies no taxes, could not use similar grounds as leverage.