David Irving, the historian jailed for three years in Austria for denying the Holocaust, is free after a court reduced his prison sentence on appeal.

Irving, who was sentenced in February, was released after Vienna's highest court ruled today that he should serve one year in prison and the remainder of his sentence on probation.

After already serving 13 months behind bars since his arrest in November 2005, Irving had his handcuffs removed today in a small courtroom crowded with his supporters and members of the local press.

"He is free, and he can leave, and he will leave," said Herbert Schaller, his lawyer, adding that he would advise the historian to leave Austrian soil as soon as possible.

Irving, under strict instructions not to talk to journalists, did not confirm whether he would be flying to Britain but shook hands with his supporters and returned to prison to pick up his belongings.

He left court triumphant and, by coincidence, to a blast of Mozart, which was being played in the courthouse to celebrate the appointment of a local judge.

Irving, 68, entered court this morning with the possibility that his sentence could be increased rather than reduced. After his conviction on February 20, lawyers for both sides had appealed, with the prosecution arguing that the disgraced historian should serve closer to the maximum 10-year sentence allowed under Austria's stringent Holocaust denial laws.

Irving's conviction was upheld by Austria's highest court at an earlier appeal in September.

A warrant for Irving's arrest was first issued in Austria in 1989, after the historian had questioned the extent and character of the Nazi attempt to annihilate Europe's Jews. Irving, who was left bankrupt and discredited by a high-profile libel trial in Britain in 2000 about his views on the Holocaust, was arrested by police after arriving in the country to give a lecture late last year.

He pleaded guilty to three counts of breaking Austria's laws forbidding the denial "of the genocide by the National Socialists or other National Socialist crimes against humanity". Among the evidence against him was Irving's belief that the attacks of Kristallnacht, a pogrom against German Jews in 1938, was committed not by Nazi officials but by "unknown" people dressing up in their uniforms.

But he expressed remorse for his views and acknowledged that gas chambers did exist at Auschwitz, the main death camp of the Holocaust, a fact he had questioned in the past.

The prospects for Irving's appeal appeared to have been damaged just a week after his conviction, when in an interview with the BBC, he continued to question the responsibility of Adolf Hitler in the Holocaust and the estimate of 6 million dead that is commonly used to describe the genocide.

"Given the ruthless efficiency of the Germans, if there was an extermination programme to kill all the Jews, how come so many survived?" He asked, before repeating his belief that Hitler's involvement in the Final Solution had "a big question mark behind it".

Local media reported today that prosecution lawyers could attempt to file fresh charges within days based on interviews that Irving gave from his prison cell but that once he left the country, it was unlikely he would ever be charged.