French President Nicolas Sarkozy has ended his state visit with a call for a new fairer world.

In a speech in the City of London, he said he was "deeply concerned" with what was going on with commodities, particularly oil.

"I'm worried to know that when I was minister of finance, a barrel of Brent was $42 (£21), right now it stands at $100 (£50), give or take a few dollars," he said.

"And yet it costs the same amount to extract that same barrel of Brent."

The president said one could not talk about a stable world when some countries did not have electricity several hours a day, while others did not know what to do with earnings they got from commodities.

"I wanted to say to the British Government, we mustn't defend the established order, we've got to defend a fair world order."

Mr Sarkozy said that while he championed freedom and competition, there was a need for rules and regulations, and France would be imposing tough rules on companies in terms of carbon emissions.

"We have to safeguard the future of our planet and our children," he said.

At a joint press conference with Prime Minister Gordon Brown earlier in the day, Mr Sarkozy refused to rule out a boycott of the Olympic Games opening ceremony.

He said they had both been "shocked" by events in Tibet where a wave of anti-Chinese protests have been brutally suppressed by the authorities.

But while Mr Sarkozy said he has not yet decided whether to pull out of the opening ceremony in August, Mr Brown stated flatly that Britain will not boycott the Games.

The disagreement was the one discordant note during the visit in which the two leaders claimed that the old "entente cordiale" between the two nations had been superseded by a new, warmer "entente amicale".

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