Undercover agent who identified 1999 attacker says police are failing to keep pace with online spread of extreme ideology

An undercover informant who identified the man behind Britain’s deadliest far-right attack has warned that a similar atrocity is inevitable due to the spread of extreme ideology online.

The mole, codenamed “Arthur”, told his handler, who then informed the police, that David Copeland was behind a series of attacks that killed three and injured more than 100 over a bombing campaign lasting less than two weeks in 1999.