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

The mole, nicknamed “Arthur,” told its handler, who later informed police, that David Copeland was behind a series of attacks that left three people dead and more than 100 injured in an attack. bombing campaign lasting less than two weeks in 1999.

Arthur – who spent a decade in the British National Party as the UK’s preeminent far-right movement pushing a ‘rights for whites’ campaign in east London – met Copeland in several times in 1997.

Copeland then detonated hidden bombs for three consecutive weekends, targeting black, Bangladeshi and gay communities from London to Brixton, Brick Lane and Soho. Each device was filled with 1,500 nails and left in a solid black tote.

Arthur told the Observer: “I was shocked when I realized it was him. Copeland didn’t seem more dangerous than the others, absolutely not. He didn’t act like a protagonist. He was a young man who seemed focused on his job working on the Jubilee line.

He identified Copeland from a picture on the first page of Evening standard on April 30, 1999 and provided police with information that the man they were looking for was an avowed Nazi and a member of the BNP. Until then, police had no idea Copeland belonged to the far right.

However, Arthur’s crucial intelligence came too late to stop the deadliest bombshell, which exploded hours later at the Admiral Duncan pub in Soho, the heart of the capital’s gay community. Three people died, including a pregnant woman, and 79 were injured, many seriously.

Shortly after the attack, Copeland was arrested and sentenced to six life sentences in 2000 for the bombings.

Yet Arthur – whose identity remains a well-kept secret – now warns that the availability and accessibility of extremist ideology online means another British far-right attack is a certainty.

He said: “Whether blatantly Nazi or racist, it is much easier to put material on the internet than to push a flyer through a door like in the 90s.

“We will definitely see another David Copeland. But that person, she or she, must know that they are also going to ruin their life. Copeland has had those three weeks of excitement and now he’s stuck in jail for maybe his whole life. It’s not just a bad thing to do, it’s a really dumb life option.

His warnings follow a wave of arrests for far-right terrorism, the latest coming on Wednesday when two men accused of spreading “far-right material” were detained in dawn raids at their London home.

Days earlier, Michael Nugent, 37, of Ashford, Surrey, had been convicted after sharing textbooks in online discussion forums about making explosives and delivering bombs in Amazon packages.

Arthur’s journey into the inner circle of the far right began in 1994 when he approached Nick Lowles of the anti-fascist group Searchlight, which specialized in dealing with “sources” within far-right groups. and then evolved into the charity. I hope not to hate. He told Lowles he was ready to go undercover.

“Most of the people we deal with have ‘turned around’ – they started out as fascists and nazis, but over time they decided what they were doing was wrong and came to us,” said Lowles.

“What Arthur did was rare: very rare. There were others who occasionally went to far-right meetings or joined a group for a few weeks or even months, but coming in for 10 years was remarkable. He never asked for money and was never interested in fame, ”said Lowles, who is now CEO of Hope not Hate.

Arthur didn’t even attempt to claim a share of the £ 70,000 reward for identifying the nail bomber.

In total, he attended more than 400 meetings, rallies and leaflet sessions, providing detailed information that anti-fascists would use to disrupt far-right operations. Arthur met Copeland nine times, each noted in his meeting reports, and had an address for him in Barking.

Copeland first struck on April 17, 1999, leaving a duffel bag containing a bomb in Brixton that injured several people, including a baby who had a three-inch nail embedded in his skull.

The following Saturday, an explosion near Brick Lane in east London injured 13 people. This was followed by the nail bombing of Soho.

Attacks are the subject of new Netflix documentary, Nail bomber: manhunt, released this week. Lowles believes the case remains important today as it exposed how police failed to take far-right terrorism seriously, an approach which he says only changed after the MP’s murder of Jo Cox by a right-wing extremist in 2016.

“The police had no record of Copeland, as he attended events all the time and he was even photographed with [BNP leader] John Tyndall, ”said Lowles, who also wrote a delivered on the Copeland informant.

He added: “Arthur was on the far right during a particularly violent time. He attended Holocaust denial events, as well as concerts by skinheads that erupted in violence, and meetings where the leaders of Combat 18 urged the public to kill their opponents.

Arthur admits his decade of infiltration was both frightening and dangerous, having at times had to deny he was “the mole” and once attacked with a hammer by an anti-fascist activist.

“By the time the danger level appeared on me, I didn’t have the bottle to say I was scared,” Arthur said.