A teenage boy who took a loaded shotgun, 200 rounds of ammunition and a mask into a school has admitted possessing the weapon with intent to endanger life, a court heard.
The 15-year-old told a 999 call handler he had “a change of heart” and had been thinking of harming others.
Police arrested the boy after being called to Higham Lane School in Nuneaton on Tuesday.
He has been bailed for sentencing at Warwick Crown Court next month.
Leamington Spa Youth Court heard the teenager, who cannot be named because of his age, also took ear plugs and a lock-knife with him to the school after removing the shotgun from a secure cabinet belonging to a relative.
Prosecutor Omar Majid said the shotgun and ammunition was legally held by an adult known to the boy.
Mr Majid told the court the boy had gone into a room in the school and taken out the items, but had a “change of heart” and decided to call police, confirming the gun was loaded.
“He said ‘I don’t know why I’ve got it, I just felt so angry this morning and I had to get it out’, Mr Majid said.
“He was asked if he was thinking of using the gun on himself or others and he said ‘somebody else’.”
During the call, the youth also indicated that he had been feeling low and had suicidal thoughts.
Warwickshire Police charged the boy with possession of a firearm with intent to endanger life, possession of ammunition with intention to endanger life and possession of an article with a blade on school premises.
Adjourning the case for pre-sentence reports to be drawn up, chair of the bench Sue Robertson told the boy to expect a sentence in excess of two years.
In a statement on the school’s website, head teacher Phil Kelly assured parents the school “will continue to be vigilant and will take all necessary precautions to ensure our children’s safety”.