A TWISTED paedophile who trawled the internet for footage of childrenbeing raped has avoided a jail term.

A sheriff decided that prison authorities could not cope with vile Duncan McAlister’s medical needs.

The pervert has brittle bone disease and can’t walk.

Instead he has been sentenced to three years probation, with psychiatric treatment, and has been placed on the sex offenders’ register for three years.

Ayr Sheriff Court heard earlier that McAlister had almost 500 indecent images on his computer, some of which were at the most sadistic level on a scale used by prosecutors.

The 24-year-old searched for ‘pre-teen paedo’, ‘toddler little girl’, ‘dog child porn’ and ‘child rape’.

Depraved McAlister also searched for ‘Maddie porn’, but prosecutors are unable to confirm if this is in relation to missing Madeleine McCann.

He spent two years downloading the material, from March 2007 until the day before his house was raided by police on March 2 2009, and even teamed up with other perverts to share the disgusting images and footage.

The wheelchair-bound paedophile pleaded guilty to taking or permitting to be taken indecent images of children.

But despite the sickening details of the crime, Sheriff Jack McGowan decided against sending McAlister, who lives at his parents’ home in Craigholm Road in Ayr, to jail.

Defence lawyer Peter Lockhart was barely on his feet in the court when the sheriff announced that he was persuaded not to imprison McAlister.

The sheriff said: “These are very serious matters and I have considered everything very carefully.

“I’ve considered carefully whether I need to send you to prison or if there is any other way I can deal with this.

“These images were solely for your own use, bad and all that is, you were not involved in the distribution of them.

“I’m conscious of your personal circumstances. You are not able to live independently, you can’t walk or even go to the toilet on your own.

“It’s highly unlikely that the prison authorities would be able to provide for you. They don’t have the facilities to deal with your needs.”

Sheriff McGowan added: “You have co-operated fully and have been open and honest about how you came to be involved in this.

“If I did send you to jail, it would probably end up being for a few weeks. I’ve no doubt you’d be released as early as possible, which means there would be no opportunity to do a lot with you.

“Only a community based disposal could deal with your psychiatric problems.”