Opec will not cut production even if the price of oil falls to $20 a barrel, the cartel’s de facto leader said, spelling out a dramatic policy shift that will have far-reaching implications for the global energy industry.

In an unusually frank interview, Ali al-Naimi, the Saudi oil minister, tore up Opec’s traditional strategy of keeping prices high by limiting oil output and replaced it with a new policy of defending the cartel’s market share at all costs.

“It is not in the interest of Opec producers to cut their production, whatever the price is,” he told the Middle East Economic Survey. “Whether it goes down to $20, $40, $50, $60, it is irrelevant.”

He said the world may never see $100 a barrel oil again.

The comments, from a man who is often described as the most influential figure in the energy industry, marked the first time that Mr Naimi has explained the strategy shift in detail.

They represent a “fundamental change” in Opec policy that is more far-reaching than any seen since the 1970s, said Jamie Webster, oil analyst at IHS Energy.

“We have entered a scary time for the oil market and for the next several years we are going to be dealing with a lot of volatility,” he said. “Just about everything will be touched by this.”

Analysts say that Saudi Arabia is throwing down the gauntlet to all the high-cost sources of crude — from the oil sands of Canada and US shale to deepwater Brazil and the Arctic — in an attempt to face down the threat they pose to its market share.

Mr. Naimi said that if the kingdom reduced its production, “the price will go up and the Russians, the Brazilians, US shale oil producers will take my share.” (...)