AS the price of crude oil hit new record highs on the world's exchanges yesterday and the average price of a litre of petrol in Britain breached the 90p barrier, Kerr-McGee, the American oil and gas company, confirmed weekend speculation that it is to sell off its entire interests on the UK continental shelf.

The Oklahoma City-based independent helped pioneer exploration for hydrocarbons off the coast of Britain in the 1970s.

Its North Sea reserves still account for a fifth of all the oil assets on its books.

So this sudden exit, against that backdrop of soaring prices, looks somewhat surprising.

True, other majors have been offloading some of their North Sea stakes to a new, hungrier breed of smaller operators.

Kerr-McGee was in the process of doing something similar. But this agreement - to sell its interest in 10 oil and gas fields to the world's largest shipping group, AP Moeller-Maersk, for dollars- 2.95bn and dispose of the rest of its North Sea interests to privatised UK utility, Centrica, for dollars- 566m - is not about fine-tuning existing strategy. It's about getting out of a mature oil province altogether.

And that's bound to revive debate about the North Sea's ability to go on competing, even in a world so desperate to get its hands on oil and gas that prices just keep on rising.

But before anyone tries to use this particular exit to revive fears that the North Sea, as an oil and gas province, is now well into its twilight years, there's another factor in this particular corporate decision that's got nothing to do with the black stuff or the North Sea's ability to keep pumping it at a profit.

It's the looming presence on Kerr-McGee's share register of Carl Icahn, one of that celebrated band of corporate raiders who, in the 1980s, sent icy shivers through some of the biggest boardrooms in corporate America.

Once described as a renegade capitalist, New York-based Icahn is now a multi-billionaire who has endowed his old university, Princeton, with a genomics laboratory. But although he'll be 70 next year, his appetite for targeting under-performing companies and making money from them, even when he's ultimately forced to walk away, remains undiminished.

Earlier this year, supreme greenmailer Icahn waged a threemonth proxy battle with KerrMcGee, demanding seats on its board.

What he and his co-raider got instead was a deal, in April, that the oil independent would buy back as much as 29- percent of its stock.

It has taken on heavy new debt to finance this buy-back.

And to fund that debt it is now selling off assets. Apart from the North Sea sale, Kerr-McGee is also flogging off its chemicals business. In return, Carl Icahn has agreed a boardroom truce.

But he's also going to pocket another handsome profit on his investment.

That's what he's done time and time again. That's how he turned himself into a multi-billionaire.

In the 1980s Icahn pounced on another American oil company, Texaco, when it was already gravely weakened by losing a legal dispute with rival Pennzoil over who should get to take over Getty Oil.

Texaco had been forced into bankruptcy protection when a judge ruled it should pay Pennzoil over dollars- 10bn in damages. Icahn turned the screw by launching a hostile takeover bid. Texaco had to sell off some dollars- 7bn of assets before it could see him off.

Icahn doesn't just target oil companies. He's mounted raids on USX, then the biggest steelmaker in the US, and even owned the airline TWA for a time.

More recently he made serious money out of biotech company ImClone, at the very time domestic goddess Martha Stewart was headed for jail for dabbling in its shares on the basis of inside information.

Ironically, Icahn was buying his shares the very day Stewart was trying to offload hers.

Recently there's Carl Icahn versus Blockbuster, the video rental franchise, where he broke into the group's quarterly conference call with analysts to argue strategy with its CEO, John Antioco.

Time Warner's shares were trading heavily last week on rumours that stake-holder Icahn was sniffing around again.

Even in the spiritual heartland of unfettered capitalism, corporate raiders draw mixed reviews.

To purists they are the necessary grit in the capitalist oyster, an effective way of giving underperforming executives a therapeutic shake-up.

However, critics view them as self-serving opportunists, asset strippers by another name, who line their own pockets at the expense of viable businesses, forced to offload assets to appease and aggrandise the cuckoo in the share register.

Carl Icahn clearly knows he's not universally held in the highest esteem.

"You learn in this business, " this normally tight-lipped philosophy graduate once observed, "if you want a friend, get a dog."