Liam Lyburd has pleaded guilty to nine counts of possessing pipe bombs, explosives, a 9mm handgun and expanding ammunition, but denies intent to endanger life.

Lyburd is on trial accused of an alleged plot to attack Newcastle College on November 3 last year.

He told a girl on Skype of his desire to kill and referenced the Anders Breivik massacre in Norway and the Jaylen Fryberg college attack in the US, the court heard.

Lyburd used online names including The Joker and I Love My Anger and also discussed attacking Newcastle Metro commuters with a gun and machete while on valium, a jury was told. 

The court heard that police found the weapons in his bedroom in the Newcastle house he shared with his mother and sister after he posted threats on Facebook.

Prosecutor Nick Dry told the court that when Lyburd was arrested he told police he was planning "to shoot a bunch of people" that day and they had saved lives.

Mr Dry said Lyburd had bought the gun online using bitcoin and told the police in an interview: "I wanted to kill them people ... there's no question."

The jury heard Lyburd later changed his story and denied making the admissions.

"In subsequent interviews he either made no comment or maintained that although he had obtained the gun, ammunition and chemicals to make the bombs it had all been a fantasy that he had not intended to actually carry out," he said.

The teenager's hatred for the college originated during a five-week spell as a student there in 2012, the court heard.

Records show he was "disruptive" and had a poor attendance record and he had been kicked out for "shocking" behaviour.