Get ready for war.

Professor Paul Rogers, of Bradford University's peace studies department, said Britain and America are likely to go to war in Iraq within days.

And Prof Rogers, an expert in war and conflict resolution, said he believed any invasion could cause massive civilian casualties.

The former head of the peace studies department said he also believed war - no matter how short - could prove counter-productive as it encouraged extremists to join the Al-Qaeda cause.

Prof Rogers, in a weekly web broadcast on the Iraq situation by the peace studies department, said he feared the United Nations was no longer seen as relevant by the allies.

"The Security Council seems very unlikely to give further full approval for a war," he said.

And that, he suggested, would not deter the Americans.

"The signs are that the United States intends to go to war to terminate the Saddam Hussein regime more or less whatever happens, with or without further UN sanction," he said.

But it could be at a great cost.

"This war is likely to cause heavy civilian casualties even if attempts are made to avoid them."

And he said people should be prepared for the fighting to begin within days.

"A war will probably start between March 20 and 28," he said.

But the respected academic said the US was not likely to be alone as it crossed the border from its bases in Kuwait into Iraq.

"Britain looks likely to go in with the United States which could cause considerable political controversy within Britain itself," he said.

And Prof Rogers said he believed the initial attacks would be ferocious in a bid to oust Saddam Hussein.

"From what we know, the United States' war plan calls for extremely intensive air bombardment lasting maybe three to four days, at a level of intensity using precision guided munitions very much higher than in the 1991 war with a possibility of shocking the regime into some sort of surrender or capitulation," he said. And it won't just be guided bombs used.

"It's probable that a ground war will start almost immediately, not least because of the perceived need to lift airborn troops into the oil field areas to protect Iraqi forces from sabotaging their own oil fields."

And the perception that the Americans want to control Gulf oil could cause it - and the UK - major problems in the future.

"The effect of replacing Saddam Hussein with what would be essentially a client regime of Washington in Iraq, even if the war is a very quick one with low casualties, will essentially aid the recruitment into organisations such as Al-Qaeda, since these organisations have claimed all along that one of the main purposes of US policy in the region is to control oil supplies," he said.