Laying bare Anglo-French divisions, the French president declared that war was the "worst possible solution" as he called for UN weapons inspectors to be allowed to continue their work.

"I note that the inspection system has proved very effective in the past," Mr Chirac said at the end of yesterday's Anglo-French summit in Le Touquet. "I note that in the first round, more arms were destroyed than in the Gulf war. Therefore the inspection system is very effective."

Mr Chirac's remarks set him directly at odds with London and Washington, which believe that Baghdad's refusal to cooperate with the inspectors has made their work all but redundant. Britain and the US have declared Iraq to be in "material breach" of UN resolution 1441 - which they believe is enough to trigger war.

Standing next to Mr Chirac, a stern-faced Mr Blair made no attempt to hide his disagreement. "Of course there are the differences that are familiar to people," the prime minister said at the post-summit press conference.

Last night France's demand that more time be given to the weapons inspectors was dismissed by the foreign secretary, Jack Straw. He wrote in a letter to the Times: "We must not allow endless calls for more time to become a cop-out."

He said the UN had to face up to its responsibilities to deal with the issue of Iraq's defiance, not defer it.

The stark differences between the two sides highlight the formidable challenge Britain faces in winning round the French. Mr Blair is determined to win French support because it would pave the way for a second UN security council resolution - a key demand of sceptical Labour backbenchers.

The prime minister knows, however, that he has only another six weeks after George Bush told him last Friday that his patience would wear thin by next month.

Downing Street officials, who privately believe that Mr Chirac will eventually be persuaded to come on board, were not surprised by the French president's barbed remarks. On the day that France's only aircraft carrier was dispatched to the Gulf, they also took heart when Mr Chirac held out the possibility of rallying behind Britain and the US.

Mr Chirac repeatedly refused to be drawn on whether France would wield its veto on the UN security council if Britain and the US attempted to press for a second resolution authorising military action. "France will assume its responsibility as it sees fit," he said.

He added that he would await the outcome of the next report to the security council by the chief weapons inspector, Hans Blix, on February 14. His remarks were echoed by Mr Blair, although the prime minister indicated that Britain regarded February 14 as more of a deadline for Iraq to prove its compliance.

"We have then the report of Dr Blix, the chief inspector, on the 14th of February. We will make our judgments then," Mr Blair said.

Divisions on Iraq overshadowed the summit, held in the British-designed northern resort of Le Touquet to underline Anglo-French ties after a series of recent rows. At the end of nearly five hours of talks, which included a lunch of scallops and lamb at the Hotel Westminster, a favourite of Edward VIII, the two leaders hailed a series of agreements on defence, education and asylum.

Mr Blair made a gesture to his host by using his halting, schoolboy French to declare: "There are more things that unite us, than divide us."