Neo-Nazi Alfie Coleman has been sentenced to 13-and-a-half years in prison.
Coleman, 22, was caught planning a mass gun attack. He was snared by MI5 in an undercover sting.
He was found guilty of preparing for terrorist acts in an Old Bailey retrial.
Previously, the court heard that Coleman was aged 14 when he first began to trawl the internet for extreme right-wing material.
That included a neo-Nazi text, which he downloaded on his iPad.
On Wednesday, he was jailed for 13-and-a-half years at the Old Bailey, with a further five years on extended licence.
Judge Richard Marks KC said that Coleman must be treated as a “dangerous offender” and described the Essex man’s views as “virulently racist”.
The judge said that Coleman claimed his views were “no more than intrusive thoughts” and “did not represent what [he] believed in real life”.
Coleman further claimed that he had no intention of carrying out an attack, the judge said.
The 22-year-old appeared tearful and wiped his eyes with a tissue as the judge made his remarks.
Commander Helen Flanagan, head of Counter Terrorism Policing London, said after sentencing: “It is extremely concerning that such a young person was planning to murder innocent members of the public as part of an extreme right-wing terrorist plot.
“But thankfully Counter Terrorism Policing, working with our colleagues in MI5, were able to intervene and arrest him before he was able to harm anyone, and I have little doubt that the brilliant work of all involved has prevented what could have been a real tragedy.
“What is particularly concerning is that Coleman was radicalised online from when he was just 14 years’ old, and sadly we’re seeing more and more examples of young people and children being drawn into violent extremism and terrorism this way.
“This is why I’m urging parents and carers to make sure that you are aware of what your children are doing online. While it may be difficult, it is vital that you have conversations with them, and if you are still concerned, then ACT Early and get in touch, so that they can be steered down a different path before it is too late.”
The jury in Coleman’s trial heard that he penned a “manifesto” in a diary and identified potential targets, including the Lord Mayor of London and a mosque.
The former part-time Tesco worker went on to compile a list of colleagues and customers he branded with racial slurs or as “race traitors”.
He was caught after undercover officers from MI5 engaged with him in an encrypted chat as he sought to buy weapons.
Authorities first became concerned in the summer of 2023 when Coleman, from Great Notley in Essex, became increasingly active on online extreme right-wing groups.
Coleman, then aged 19, arranged with an undercover officer to buy a Makarov pistol, five magazines and 200 rounds of ammunition, in a Morrisons car park in Stratford, east London, on the morning of September 29 2023.
Jurors saw dramatic video of Coleman dropping £3,500 in a Land Rover Discovery and picking up a holdall containing the handgun and ammunition from the boot.
Before he had gone 30 yards, Coleman, who was carrying his Tesco employee card, was confronted by armed counterterrorism police and forced to the ground.
A search of the home he shared with his parents and sibling revealed the extent of Coleman’s murderous ideology, including idolising Thomas Mair, the extremist who killed MP Jo Cox.
Police found £2,500 in savings and a device to detect bugs and secret cameras in his bedside drawer; a rock with a Swastika on a table; a Black Sun flag associated with neo-Nazism on the wall; and various extreme right-wing books.
Giving evidence, Coleman described being lonely and suffering with his mental health during the Covid-19 lockdowns.
Coleman had admitted attempting to possess both a firearm and ammunition but denied he was preparing for a terrorist attack.
He had pleaded guilty to possessing 10 documents with information likely to be useful to terrorists such as texts on weaponry and bomb-making instructions.
