I never would have heard of Anjem Choudary, founder and leader of the now banned group al-Muhajiroun, if I hadn’t seen him on British TV. A lot. He wasn’t the infamous preacher of hate the media wanted him to be. He was a scrappy street agitator. Or, he was, until he got his big break.

His rise from anonymity to the halls of the BBC was astounding. During a certain period, if there was a TV debate about Islam, Choudary would be there. It was like asking the head of the Westboro Baptist Church to put the mainstream Christian view, and I bet even he had more followers than Choudary when the media first discovered him.

His message spread not via pulpits in places of worship, but from the studios of the BBC

Now, months after Choudary was finally convicted for supporting Islamic State, a connection has reportedly emerged between the deadly rampage on London Bridge and his network. The media took a ragged, cynical opportunist who, by himself, had garnered little traction, and gave him an aura of authority. His message was hugely amplified.

The first time I encountered Anjem Choudary in real life, I was struck by one thing: how good he was at creating a spectacle and attracting attention, given his own lack of importance. He knew how to play a media that was begging to be played. He gave them what they wanted – a show. He had a knack for gathering a small bunch of loudmouth supporters and shoving them in front of TV cameras and photographers’ lenses. The broadcasters and publications behind them were eager to participate because the images were so striking.

With no qualifications and a tiny, ramshackle following, he nevertheless appeared on BBC Newsnight, BBC News, Radio 4’s Today programme, Channel 4, GMTV, CNN and CBS news, not to mention the newspapers. He could always be relied upon for an incendiary quote, so he was booked again and again. Every time he fell too far off the radar for his liking, he would find another way to make an exhibition of himself and draw the media back in. In late 2013, he and a dozen or so supporters participated in a “march against alcohol” in London’s East End (where thousands of Muslims have happily lived cheek-by-jowl with pubs and bars for decades). It was picked up by almost every major paper in the country, despite the fact that there were more police there than al-Muhajiroun supporters.

By the time he was convicted last year, Choudary was a public figure, the media attention that created him having become self-sustaining. He and his handful of gangsters had been turned away from mosques and shunned: his message spread not via pulpits in places of worship, but from the studios of the BBC.

It doesn’t feel gracious to say this, but we told you so. Muslim journalists and activists spent years tearing their hair out in frustration at the platform Choudary was given. Many spoke out against this disproportionate exposure and boycotted shows he was invited on. In 2010 Mehdi Hasan condemned a “sensationalist and irresponsible media” that had been “deeply complicit in the rise and rise of this fanatic”. In 2009 I reported on an al-Muhajiroun stunt that the media lapped up, saying that I was “loth to dismiss them as the joke that they manifestly are” because they knew how to get attention.

And this wasn’t some kind of natural process that no one could have halted. Choudary was chosen by editors and bookers quite conciously. Some, such as James O’Brien, complained about it for years. Last year it was reported that radio presenter Iain Lee claimed that he “got flak” for cancelling an interview with Choudary on BBC Three Counties Radio.

And still, lessons have not been learned. Broadcasters who remain committed to hateful self-publicists such as Katie Hopkins for the sake of “debate” would do well to consider Choudary’s example.

It is too late to put that particular genie back in the bottle, but not past time for the media to begin to take responsibility for the real-world effects of their poor choices. They can, after all, cost lives.