He had pleaded innocent when his case was heard earlier this year but was convicted, banned from driving for a year, and ordered to pay a �250 fine plus �300 costs.

The 56-year-old Daily Mail journalist was stopped by police while driving his Honda in west London last October.

"According to the police officer, he blew around the tube rather than into it, and rather than continuously, blew erratically," the prosecuting barrister, Peter Ader, told Knightsbridge Crown Court on Thursday.

"The machine is designed so that it will not register a reading when that happens."

'Blood aversion'

Dempster was arrested and taken to the nearby Hammersmith police station where a second breath test indicated an alcohol level of 45 microgrammes of alcohol per 100ml of blood - 10 higher than the legal limit.

The law demands that a blood or urine sample be taken to confirm the result and the police have the right to decide which should be used.

"He wanted to give urine because he had an aversion to giving blood as he suffers from blood injury syndrome," Mr Ader said.

But a doctor who examined him at the time "was not satisfied that the reason for refusing to give a specimen of blood was clinically justified".

When the case came to trial, Mr Dempster testified he was "terrified" of needles.