A sixth-grade teacher in Abbotsford, B.C. has been stripped of his teaching licence after admitting he downloaded porn on his classroom computer.

In a March 14 decision, the B.C. College of Teachers ruled that Carl Williamson of the Mennonite Educational Institute will be disqualified for teaching for the next 20 years after he was caught on camera viewing pornographic images of adult women at school.

During the college's investigation, Williamson also admitted to having sexual thoughts about students between the ages of 12 and 18.

Mykle Ludvigsen, spokesman for the college, told ctvbc.ca that Williamson will have to undergo a "fitness review" if he decides he wants to teach again after the 20-year suspension is over.

If he applies to teach anywhere else in North America, he'll have to produce a record of his professional standing when he applies for a licence.

"It would be very difficult for him to find work in another jurisdiction," Ludvigsen said.

According to the college's conduct review decision, Williamson first admitted to looking at porn in the classroom in July 2006. He signed an agreement with school officials promising to stop, but six months later, he acknowledged that he had breached the agreement.

The college reviewed Williamson's behaviour in 2007, but took no action, finding that he understood the professional standards for teaching.

Then in 2009, the school opened an investigation when security cameras caught Williamson viewing porn yet again. He admitted to officials that he had spent $8,000 on prostitutes over the last 18 months.

Williamson was suspended from his position in January 2010, and his teaching licence was temporarily suspended by the college in April, pending completion of its review.

He was also investigated by police, who searched his classroom and home computers and found adult pornography on both. No charges were laid.

On his Facebook page, Williamson describes his job at the school as "Teaching, marking, yelling at kids..." He says he has taught at the school since 1997.

In the past, he's also worked as a boys' soccer coach for the Abbotsford Mariners. In an email, the soccer club's president told ctvbc.ca that Williamson has not coached with the Abbotsford association since 2008, when the club learned of the allegations against him.

The Mennonite Educational Institute was closed for spring break on Wednesday, and school officials could not be reached for comment.