London ? David Irving, the British author who was released on probation after spending 13 months in an Austrian prison for denying the Holocaust, said Thursday he felt no remorse for his views.

Irving spoke upon returning to England a day after Vienna’s highest court granted his appeal and converted two-thirds of his three-year sentence into probation.

At London’s Heathrow airport, Irving said he had been obliged to express regret during the court case but now had “no need any longer to show remorse.” He also called for a boycott of all Austrian and German historians until laws making Holocaust denial a crime in those countries are overturned.

Irving had been sentenced in February to three years under a 1992 law that applies to “whoever denies, grossly plays down, approves or tries to excuse” the Nazi genocide or other Nazi crimes against humanity in a print publication, broadcast or other media.

The author, who has been banned indefinitely from Austria, spent the night in a detention center, said Willfried Kovarnik, head of Vienna’s immigration police. Irving said he intended to appeal the decision to ban him from Austria.

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.