A 15 year old boy from Blackburn in northern England pleaded guilty on Friday to planning an ISIS inspired terror attack at an ANZAC day parade in Melbourne, Australia.
The boy, aged 14 when he was arrested, was not named publicly for legal reasons.
The court announced that the 15 year old will serve at least five years for orchestrating the terror plot and will only be released once he is no longer seen as a potential danger to the public.
The defendant's lawyer, James Pickup QC, acknowledged the fact that the boy was "dangerous" for a short while, but noted that since his arrest there had been "considerable...substantial change" for the better.
The boy's solicitor, Daniel King, said the family was "shocked and devastated" when he was arrested and stated that they had no idea about his intentions.
The 14-year-old teenager was arrested on April 2 on suspicion of planning an act of terror. On April 18 he was further arrested on suspicion of being involved in the commission, preparation or instigation of acts of terrorism.
Police reportedly discovered communications between the boy and Sevdet Besim, 18, who was also charged in Australia over the ANZAC day terror plot.
The teenagers are thought to have met through ISIS recruiter Abu Khaled al-Cambodi.
ANZAC day is an event which commemorates the fighting of Australian and New Zealand soldiers at the battle of Gallipoli in Turkey.
Australia has concerns about ISIS luring young Australians to join the conflicts in Syria and Iraq.