A senior Catholic priest who was caught with 18,000 indecent photographs and computer images of children has been jailed for nine months.

Father Michael O'Kelly, the former Dean of Reading, had pleaded guilty to a single charge of making indecent pseudo-photographs of a child between June 1997 and October 2000.

The court was told the images - found on videos, magazines and computer discs - were "disturbing, degrading and disgusting".

What I was doing in private was destroying what I did in public - it was my guilty secret

Father Michael O'Kelly

The 47-year-old priest, who has been receiving treatment at Horton Hospital in Surrey, was also sentenced to a six year supervision order, placed on the sex offenders' register and banned from working with children.

He appeared at Reading Crown Court for sentencing on Monday.

The priest - a former African missionary - said in police interviews that he ran up phone bills of up to �1,500 a month as he accessed the internet, downloading images and visiting chatrooms.

"What I was doing in private was destroying what I did in public - it was my guilty secret," he said.

"I was afraid but I followed. I simply did not, or could not, control it."

What you have done assists to perpetrate the abuse of children

Judge Stanley Spence

The priest was arrested following a raid at his home in Tilehurst near Reading by Thames Valley Police and Customs and Excise officers.

Prosecutor Neil Moore said at least 70% of the images contained children involved in sex acts.

He said there was no evidence O'Kelly had passed on the images or shared them with other people.

Defending, Jennifer Edwards said O'Kelly had been highly motivated to co-operate with police.

Judge Stanley Spence said that up until 1997 he had no doubt O'Kelly was a good priest.

"But what you have done assists to perpetrate the abuse of children, the mere fact that you have indulged in it perpetrates those who assist in this awful treatment of children," he said.