Holocaust denier David Irving was booked on a flight to return home to Britain on Thursday, a day after a court granted him early release from a three-year prison sentence, but fog in London delayed his departure.

Irving, 68, was booked on an afternoon flight on Austrian Airlines, and he was to be escorted to the airport by police, his office told The Associated Press. But airline representatives said the departure was delayed because of the bad weather in London.

Vienna's highest court on Wednesday granted Irving's appeal and converted two-thirds of his sentence into probation. He had been imprisoned for 13 months.

The author, who has been indefinitely banned from Austria, spent the night in a detention center, said Willfried Kovarnik, head of Vienna's immigration police.

In February, a Vienna court sentenced Irving to three years under a 1992 law that applies to "whoever denies, grossly plays down, approves or tries to excuse the National Socialist genocide or other National Socialist crimes against humanity in a print publication, in broadcast or other media."

The law calls for a prison term of up to 10 years.

During his one-day trial earlier this year, Irving pleaded guilty to the charge of denying the Holocaust but maintained he never questioned it in the first place.

The defense and the prosecution appealed the sentence. In September, Austria's Supreme Court upheld Irving's conviction.

Irving has been in custody since his November 2005 arrest on charges stemming from two speeches he gave in Austria in 1989 for which he was accused of denying the Nazis' extermination of 6 million Jews. He has contended that most of those who died at concentration camps like Auschwitz succumbed to diseases such as typhus rather than execution.