Britain faces a new threat of terrorism from “extreme violence carried out by loners, misfits, young men in their bedrooms” following the Southport murders, the Prime Minister has said.

Axel Rudakubana, 18, pleaded guilty on Monday to murdering three girls at a Taylor Swift-themed dance class in Southport, Merseyside, in July.

Despite contact with state agencies such as Prevent, aimed at countering terrorism, authorities failed to stop the attack which claimed the lives of Alice da Silva Aguiar, nine, Bebe King, six, and Elsie Dot Stancombe, seven.

Axel Rudakubana pleaded guilty on Monday (Merseyside Police/PA)

Home Secretary Yvette Cooper announced an inquiry into the case on Monday evening, saying the country needed “independent answers” on Prevent and other agencies’ contact with the “extremely violent” Rudakubana and “how he came to be so dangerous”.

Addressing the nation on Tuesday, Sir Keir Starmer said: “The predominant threat was highly organised groups with clear political intent – groups like al Qaida.

“That threat, of course, remains but now alongside that we also see acts of extreme violence perpetrated by loners, misfits, young men in their bedroom accessing all manner of material online – desperate for notoriety, sometimes inspired by traditional terrorist groups, but fixated on that extreme violence, seemingly for its own sake.”