A TEENAGER, who thought it was "funny" to start a fire which destroyed a school gym, will spend the next nine months behind bars.

The PE block at Chester-le-Street's Hermitage School was demolished in the blaze, which caused £1.2m worth of damage.

A 16-year-old youth, arrested ten days after the fire, appeared at Durham Crown Court yesterday.

He previously admitted arson and was sentenced to 18 months' detention and supervision, the first half of which will be spent in custody.

A co-accused, now aged 17, denied arson, but admitted burglary, and was given a 150-hour community punishment order, after the prosecution accepted his plea.

The court heard they entered the school with other youths after the 17-year-old smashed a window, late on Friday, November 2.

Others left, but the two defendants entered the gym, where the 16-year-old ignited a jumper with a cigarette lighter, starting the blaze.

Police on patrol saw the gym block on fire and called the fire brigade.

Twenty-four firefighters were needed to tackle the fire.

The gym was left unstable, and following assessment it was written-off by the education authority.

David Callan, prosecuting, said, following their arrest: "Both seemed to think it was funny, but later appeared to have realised the seriousness of what they had done."

He said a scenes of crime officer found a box of firelighters on the school steps.

Gavin Doig, for the 16-year-old, who works for a window company, said it took place while he was "in drink".

Brian Russell, for the 17-year-old, a trainee electrician, said the break-in was his idea, as he had seen two bottles of wine on the premises.

"It was undoubtedly a stupid action which had devastating consequences for the local community."