Jurors have failed for a second time to reach a verdict in the terror trial of a teenager accused of planning an attack on his old school in a repeat of the Columbine massacre.
Prosecutors alleged Michael Piggin, 18, stored petrol bombs, air rifles, pistols and armour in his home, which he planned to use against staff and pupils at his former high school in Loughborough, Leicestershire.
He faced a retrial at the Old Bailey after an earlier jury could not decide on a verdict.
But the fresh jury of six men and four women, which had been deliberating since 13 May, was discharged on Friday after it was unable to reach a verdict.
The prosecution confirmed that there would be no retrial.
Police discovered the stash when they were called to investigate a public order offence at Piggin’s home in Beaumont Road, Loughborough, in February last year.
Piggin and two other teenagers, who cannot be named, had admitted charges of possessing petrol bombs and component parts of pipe bombs for the use of explosive devices, the jury was told.
He has also admitted possessing the component parts for improvised explosive devices (IEDs).
But Piggin, who has Asperger's syndrome, pleaded not guilty to two charges under the Terrorism Act.
He denied possessing items for the purpose, preparation and instigation of an act of terrorism and possessing a document or record containing information likely to be useful for a person committing or preparing an act of terrorism.
Prosecutor Gareth Patterson indicated the Crown would not be seeking a further retrial saying: “If this jury cannot return verdicts that will be the conclusion of proceedings.”
The teenagers are expected to be sentenced for the matters to which they’ve pleaded guilty at the Old Bailey on 13 June.
The Columbine High School massacre of 1999 was one of America's worst mass shootings. Eric Harris and Dylan Klebold murdered 12 students and a teacher at the school in Colorado before both committing suicide.
Additional reporting by Press Association