Princess Diana takes a tough stance against smoking.

"You will find that there is no smoking in my house and no ashtrays either," the princess recently told an anti-smoking group on Britain's seventh annual No Smoking Day.The 29-year-old, non-smoking princess was surprised to find that her smoker's breathalyzer test registered two-parts-per-million of carbon monoxide.

That level was because she had travelled across London by car, Dr. Malcolm Green, chairman of the British Lung Foundation, told the princess.

By comparison, some smokers who took the test registered nine, 19 and 24 parts.

"That's not very good," said Diana, who is married to Prince Charles, heir to the British throne.