A heated debate over veils that cover the faces of some British Muslim women is growing ugly and could trigger riots, the head of Britain's race relations watchdog warned on Sunday.

Britons are becoming increasingly polarized along racial and religious lines, and if they don't talk respectfully about their differences, bad feeling will mount and could fuel unrest, Commission for Racial Equality chairman Trevor Phillips wrote in The Sunday Times newspaper.

An angry debate "is the last thing Britain needs," wrote Phillips, whose commission is an independent, government-funded body created by law in 1976 and charged with fighting discrimination and encouraging good race relations.

"This could be the trigger for the grim spiral that produced riots in the north of England five years ago. Only this time the conflict would be much worse. We need to chill," he wrote.

Racial tension between white and mainly Muslim south Asian youths flared into rioting in several northern English towns in mid-2001.

A debate over veils that cover all but a woman's eyes has become increasingly heated since former Foreign Secretary Jack Straw set it off earlier this month by saying that he asks Muslim women who visit his office to remove the full-face covering when they speak with him.

It touches on growing anxieties about Britain's diversity and the alienation of young British Muslims like those who carried out suicide bombings on London's transit system last year, killing themselves and 52 commuters.

Prime Minister Tony Blair jumped into the debate last week, saying Britain needed to talk about how minority communities could better integrate into the wider society while maintaining their cultural distinctiveness. He called the veil "a mark of separation."

Phillips said he thought Straw's remarks had been polite and respectful, but worried that the debate had since grown ugly and rancorous.

"I this morning really would not want to be a British Muslim because what should have been a proper conversation between all kinds of British people seems to have turned into a trial of one particular community, and that cannot be right," he told British Broadcasting Corp. television.

"We need to have this conversation but there are rules by which we have the conversation which don't involve this kind of targeting and frankly bullying," he said.

Phillips said he didn't want Britain to suffer the kind of violence that exploded in the deprived suburbs of Paris last year, when disaffected young people, many from immigrant backgrounds, rioted for three weeks.

Muhammad Abdul Bari, secretary-general of the Muslim Council of Britain, agreed the veil debate had become "increasingly ugly and shrill," and said in a statement that it had been accompanied by violent attacks on Muslims.

Some women's veils had been forcibly pulled off, mosques had been targeted in arson attacks and Muslims had been beaten by thugs, he said.