So much for “stability”, and so much for “strategic partnerships”.

The ramifications of Opec’s decision to slash production targets by another 1.2m barrels per day will be profound, though you wouldn’t know it from the “business as usual” responses from the White House and Riyadh following Sunday’s shock move.

Saudi Arabia said the cuts were a “precautionary measure aimed at supporting the stability of the oil market,” a statement instantly made to look ridiculous by the 8pc spike in global benchmark Brent crude when markets opened on Monday morning.

It was the steepest one-day increase in oil prices in more than a year, with West Texas Intermediate experiencing a jump of the same proportions to leave prices hovering around $85 a barrel.

After the sharp drop in prices following the turmoil in the banking industry, this is Saudi Arabia’s panicked attempt to install a floor to help Crown Prince Mohammed bin Salman (known as MBS) bankroll a series of mega-building projects at home that make HS2 look like it belongs on the set of Thomas the Tank Engine by comparison.

Under what has been dubbed MBS’s “Vision 2030” economic plan, the kingdom is constructing a $500bn (£400bn) futuristic “smart” city in the Arabian desert that it claims will be 33 times bigger than New York City and powered entirely by renewable energy, and a sprawling holiday resort the size of Belgium on 28,000 sq km of pristine land next to the Red Sea.

Still, the idea that ties between America and Saudi Arabia can still be called “a strategic partnership” in the face of this latest snub to Joe Biden, as national security spokesman John Kirby sought to claim, is even more preposterous, even if US officials were given a heads-up on the plan.

The worst that Kirby could bring himself to say was “We don’t think that production cuts are advisable at this moment, given market uncertainty – and we made that clear”, which threatens to be the understatement of the century. It is the second time in six months that the Saudis have delivered a massive diplomatic humiliation to the US president.