Broadcaster Richard Bacon may have been voted one of the most influential British users of Twitter, but not everyone on the social networking site is a fan. After two years of disturbing online vitriol from someone who fantasised about seeing his mangled body in a car wreck, he decided to do something about it.

The result is The Anti-Social Network (Monday, BBC3, 9pm) in which Bacon pursues cyberbullies who’ve tormented him and his family plus a growing number of innocent people. The documentary comes at a time when the 5 Live presenter is adjusting to fatherhood following the birth of his son Arthur last October, so I ask if his status as a first-time dad made him feel more vulnerable and spurred him on to make a stand.

“It does certainly feel more real and as though I have more to protect,” he tells me. “Having a baby did change the way I think about the issue to some degree. Dr Emma Short, the psychologist on the show who specialises in abuse, was the first person who advised me to go to the police. She said, ‘you’ve got a child now, you’ve got to take this seriously’. There are cases where people have posted violent abuse online and it’s crossed over into real lives. It’s very rare but it exists.

“Her point was that I couldn’t just sit there making a programme about this, she said I had to do something legally. What the chap who’s been stalking me has been doing is illegal. It crosses over into harassment and so the police are now involved.”

By the end of last week, the Twitter account of @dick_bacon_boom! had been suspended following Bacon’s meetings with the authorities. He advises anyone suffering similar harassment to do the same, as it’s not only celebrities whose lives on the net have been made a misery in this way.

Perpetrators known as trolls, who conceal their identities, make it their mission to provoke shock and outrage under the guise of being renegade operators. Does Bacon feel that this cloak of anonymity has led to a generalised increase in aggression on the internet?

“There does appear to be a strange alchemy between people typing alone at home on a keyboard and these public forums,” he says. “It brings out a nasty side where people start making strident comments that they just wouldn’t make in real life. It’s something that we hadn’t seen much of before the invention of the internet.”

And the problem is only getting worse – a recent survey of 4,600 children carried out by the charity Beatbullying and the National Association of Head Teachers found that 28 per cent of children aged 11 to 16 had experienced bullying either on the internet or via mobile phone.

In the programme, Bacon speaks to the parents and brother of 15-year-old Tom Mullaney, who last year took his own life following taunts on Facebook. Following his death, a memorial page on the site was desecrated by trolls - none of whom actually knew Tom - who posted insults, abuse and sexual “jokes”. Watching the family’s anguish, I was left feeling that social networking has a malign influence on today’s teenagers. Does Bacon agree?

“It’s not as simple as that. Social networking sites can be very entertaining and they’re becoming increasingly important, yet there is also a darker side to what they do.

“But it’s not Facebook’s fault that people become aggressive online. However, I did come away thinking that they could do more about the abuse. I don’t feel that they’re bothered about it enough. The police haven’t quite worked out what to do either because actually monitoring it all requires enormous resourcing.

“There are existing laws that you can use to prosecute people who are harassing you on the internet. The Communications Act of 2003 is there if you feel someone is causing you ‘unnecessary anxiety’ online, but the laws probably need updating. I think what’ll happen is that the abuse is going to cause more problems, but the victims are getting more of a voice now – public opinion is going to catch up with the police, the law and the social networks.”

In the meantime though, with the trolls at a technological advantage and feeling no qualms about the misery they inflict, does Bacon feel that he’s made himself more of a target by drawing attention to the issue?

“I don’t fear reprisals. I think that I’ll become a bit of a target, but I’m not worried about it at all. I’m on the right side of the argument here. It’s always going to feel much worse for those on the sharp end of cyberbullying than it is for a TV presenter who’s getting annoyed in a documentary.”

"Annoyed" is an apt word, for in The Anti-Social Network we see Bacon confronting perpetrators with damning evidence and door-stepping Colm Coss, a man who served a prison sentence for sending “malicious communications” on Facebook and who is now alleged to be re-offending. So is Bacon at ease when adopting this Roger Cook-style persona?

“It’s probably the most serious thing I’ve made, certainly the first documentary. So it’s a style of presenting I haven’t done before. It’s satisfying but I didn’t enjoy it all – I didn’t like door-stepping someone, it’s not my sort of thing. I might look comfortable with it but I’m not.”

He then adds: “But I think it’s important because this is a really serious problem. The perpetrators are adopting the names of real people and going on tribute sites to post abuse. If the family thinks abuse has been written by the person whose name the troll has adopted, then an innocent person could end up being the victim of a reprisal. Someone could die.

“These trolls think they’re being satirical and brave because they’re putting these dangerous, edgy so-called jokes on there, but in reality it’s cowardly. It’s the antithesis of bravery because they rarely identify themselves or give away personal information. That’s not courage."