LONDON - British Prime Minister Keir Starmer described the deadly Southport knife attack last July as a sign of "a new threat" of terrorism and called for changes to address this evolving danger on Tuesday morning.

The Southport knife attack resulted in the deaths of three young girls during a Taylor Swift-themed dance class.

"Terrorism has changed," Starmer stated in a statement, characterizing such threat as "acts of extreme violence perpetrated by loners, misfits, young men in their bedrooms, accessing all manner of material online."

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He emphasized the Southport attack "must be a line in the sand for Britain" and that the three girls killed must lead to "a fundamental change in how Britain protects its citizens and its children."

Starmer pledged to swiftly amend laws if necessary to "recognize the new and dangerous threat" and committed to reviewing the counter-extremist system to "make sure we have what we need to defeat it."

The 18-year-old attacker, Axel Rudakubana, who pleaded guilty to the murders on Monday, had been referred to the anti-terror prevention program on three separate occasions. However, each time, it was determined that he did not meet the threshold for intervention.

Starmer criticized these assessments as "a judgment that was clearly wrong and failed those families," acknowledging a failure that "leaps off the page."

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As part of a public inquiry into the attack announced by the government on Monday, the prime minister said "I will not let any institution of the state deflect from their failure."