With the help of technology journalist David McClelland, Em investigates this very modern menace. She is on a mission to put a face to these anonymous bullies and to confront them with their victims.

In its most extreme form, trolling is a criminal offence - one that is being increasingly pursued by the British police - but anonymity remains a major barrier to conviction. The film investigates online anonymity and proves that it is possible to track down a troll. It shines a light on the real-world impact of online bullying and encourages cyber-victims to put a stop to the hatred levelled at them by standing up to their trolls.

Trolling is a phenomenon that has swept across the web in recent years. On a daily basis, an audience of millions sits back and witnesses the ultimate humiliation of civilians and celebrities alike on social networking sites. Opponents say it is the internet equivalent of assault, while supporters argue it is about humour, mischief and freedom of speech. In any case, trolling has escalated to levels so severe that some victims are succumbing to anxiety, depression and, in the very worst cases, suicide.

Ultimately, Troll Hunters is here to name, shame and lay down the law to Britain's worst offenders and to unpick the psychology of what makes a troll tick.