A former school pupil dressed up as 'Batman' character 'The Joker 'and set fire to the building causing more than €1m worth of damage, a court heard yesterday.

Christopher Clancy (19) of Cherrywood Grove, Clondalkin, pleaded guilty at Dublin Circuit Criminal Court to arson at Colaiste Chillian on the Old Nangor Road on May 10, 2009.

Clancy, who will be sentenced later, told gardai when he was arrested at the scene that he burnt the school down "because it is run by hypocrites and I didn't like the way they treated my friends".

Garda Liam Ganny told the court that Clancy, who had left the school the previous November, filled six large jerry cans with petrol and cut his way through a wire-mesh fence to access the school grounds.

He smashed in a glass door and proceeded to spill the contents of one can along the corridor. He then lit the petrol and escaped from the school.

When gardai arrived at the scene they noticed a man dressed "in a purple suit, with green hair, a white face and red painted lips".

"He was dressed up as The Joker from 'Batman'," said Gda Ganny. "He then told us to go around the corner and we would see what he had done."

Clancy had video-recorded the burning building on his mobile phone and had planned to send the video clip to his friends.

He told gardai he had left the school five months previous to the arson attack and "that's when I planned the attack".

He purchased the jerry cans over a five-week period and hid them in the bushes near the school. He bought 100 litres of petrol from a nearby petrol station.

He told gardai: "I am glad I did it because the people will realise they can't treat students as sub-human."

The school was closed down for five days following the fire and Leaving Certificate students had to be accommodated at another school to sit their exams.

Offence

Seamus Clarke, defending, said: "The fire was contained to the back of the school and Mr Clancy did not attempt to flee the scene.

"He was 17 at the time of the offence and is an introspective and reserved person. He left school to attend Youth Reach," said Mr Clarke.

He is now with the Tower Project and plans to attend Dun Laoghaire College of Art and Design in September.

Judge Patricia Ryan said the offence "seems to be a one-off incident" and "the difficulty for the accused is that he hasn't really addressed the depressive episode".

She ordered that he attends his GP for a medical report and adjourned sentencing until October.

Irish Independent