Nigel Farage has called for Director of Public Prosecutions Stephen Parkinson to quit over the Southport attack.
The Reform UK leader criticised the Crown Prosecution Service (CPS) for not declaring the stabbings by Axel Rudakubana as terror-related.
Mr Farage said: “The judge made clear in his sentencing that Axel Rudakubana had a detailed interest in genocides and massacres, and that he was in possession of an al Qaida manual.
“This barbaric and senseless attack was clearly both political and ideological. Many crimes of much less severity have been declared as terrorism within 24 hours of the incident taking place.
“The British public needs to have confidence in the CPS and our police forces.
“Tens of millions of British citizens will find it incomprehensible how the CPS decided this was a non-terror incident and maintained that position.
“Those in positions of power have to be accountable and responsible for their actions.
“Stephen Parkinson, the Director of Public Prosecutions at CPS, should now do the right thing and resign for CPS’ negligence in this case.”
Mr Farage’s intervention comes as Rudakubana, 18, was today handed a 52-year sentence for the murders of three girls at a Taylor Swift-themed dance class.
He was sentenced in his absence at Liverpool Crown Court after indicating he would be “disruptive” if he was present in the courtroom.
Alice da Silva Aguiar, nine, Bebe King, six, and Elsie Dot Stancombe, seven, died in the attack, and Rudakubana also attempted to murder eight other children, who cannot be named for legal reasons, class instructor Leanne Lucas and businessman John Hayes.
It emerged this week that the killer had been referred to the Government’s Prevent anti-extremism scheme three times.
He was also found to have downloaded an Al Qaeda training manual and kept ricin at his family home.
Prosecutors said the case did not meet the legal definition of terrorism as there was no evidence that Rudakubana killed to further a political or ideological cause.
It comes as Mr Farage has repeatedly made claims of a “cover up” over the case, but Prime Minister Sir Keir Starmer has insisted disclosing information earlier on would have risked collapsing a criminal trial.
The CPS has been contacted for comment.
