An eminent scientist who admitted owning 500,000 indecent images of children was freed from jail by the Court of Appeal today.

The court held that the 15-month sentence passed on respected astrophysicist Robin Phillips last November was too long in view of his frank admissions and the fact that the pictures stored on his laptop computer were all in the lowest category of indecency.

Phillips, 34, based at Lethbridge University in Alberta, Canada, was caught taking photos up the skirt of a girl playing on one of the lions in Trafalgar Square.

He told police it was a "kind of hobby" and he did not realise it was illegal.

The court heard that most of his stored images, found on a computer at his parents' home near East Grinstead, West Sussex, were not created by him and many were obtained from countries where they would not have been considered illegal.

No child abuse was involved in any of them.

Phillips had now lost his employment in Canada. His wife and children had been forced to return to her homeland in Germany. His only hope was to join her there, although his sphere of work would be severely restricted because of his conviction.

Appeal judges Mr Justice Penry-Davey and Judge Stewart QC reduced the sentence to nine months, allowing Phillips to be released immediately.

Orders banning Phillips from having a camera in public for 10 years, requiring him to register as a sex offender and disqualifying him from working with children for life will remain in force.

The judges were told that Phillips had sought counselling and was highly unlikely to offend again.