Jack Straw has suggested that anti-war demonstrators preparing to give President Bush a hostile reception in London in a fortnight may be dampened by the weather.

"We do not know exactly how many will come. Much will depend at this time of year on the weather," the foreign secretary told the Guardian.

Straw made a stout defence of the "special relationship" with the US which Tony Blair has sought to protect.

"If we do not nurture this relationship, America will look both inwards and westwards to the Pacific basin," he said. "That is their choice, but it would be both bad for Europe and bad for America."