Ben KendallA teenager who sparked a major alert when he was arrested at a Norfolk high school after making threats over the internet has admitted having a knife on the school premises.Ben Kendall

A teenager who sparked a major alert when he was arrested at a Norfolk high school after making threats over the internet has admitted having a knife on the school premises.

The teenager, who cannot be named for legal reasons, was 16 at the time of the incident in March last year. He was sectioned under the mental Health Act after being arrested at Attleborough High School when police were alerted to alarming comments made in an internet chat room.

On the website, the boy boasted 'they will pay' before staging an attempt to attack the school with what he described as 'arson and violence'.

But when he arrived at the school's reception, police were waiting for him after being tipped off about the statements by a web user 4,000 miles away in Canada.

He is now in a hospital in Prestwick near Manchester and appeared at Norwich Crown Court yesterday when he admitted threatening to damage property and having articles with intent to damage property.

He also admitted having an offensive weapon, a knife, on school premises.

At the time of his arrest, the boy was carrying a knife, matches and what was believed to be canister of flammable liquid. However, he will not face charges in relation to the canister.

The boy's online alias quoted the date of the infamous Columbine massacre and he outlined every detail of his planned attack on the school. In one post he said that the school 'would go down in flames'.

Coming just a week after 15 people were shot and killed at Albertville High School in Germany, the attempt attracted national headlines.

Following his arrest police searched all pupils' bags as a precaution. They later searched the boys home address and seized his computer for analysis.

Speaking shortly after the attempted attack, Supt Katie Elliott said: 'Our priority was the safety of everyone at the school, both pupils and teaching staff, The safety of the public is and always will be our number one priority and we acted swiftly to keep the public safe.'

His case was adjourned awaiting a full psychiatric report and he will be sentenced at a later date.