INTERNET trolls could be brought before the courts under new legal guidelines.

Social media will be more stringently policed after the Crown Prosecution Service issued rules on offences for which online users can face criminal charges.

Inciting people to harass others online, known as 'virtual mobbing', is among the offences included in the guidance published on Monday.

Dr Jacqui Taylor, associate professor in psychology at Bournemouth University, said cyber-bulling can have an "awful" and "lasting" impact on victims.

"There is little that really helps beyond things like counselling," she said.

"However, if the victim knows that the offender is being prosecuted, that might at least give them some closure. I would imagine that it might help."

Dr Taylor said experts are now looking more closely at what makes internet users turn troll.

"Initially, research looked at the importance of anonymity - people are distant online," she said.

"More research has been done on the psychology."

Experts have identified a 'dark tetrad' of personality traits that can often be seen in those responsible for extreme trolling.

"These people can have psychological problems," Dr Taylor said.

"The tetrad includes sadist, psychopathic and narcissistic tendencies."

More worrying still is that internet abuse can move offline.

"It can begin online, but people share much of their lives on the internet now," said Dr Taylor.

"It isn't always restricted to the internet. It can turn into physical stalking."

A major report released earlier this year found one in four teenagers nationally have suffered abuse online because of their gender, sexual orientation, race, religion, disability or transgender identity.

Director of Public Prosecutions Alison Saunders said: "Social media can be used to educate, entertain and enlighten, but there are also people who use it to bully, intimidate and harass.

"Ignorance is not a defence and perceived anonymity is not an escape. Those who commit these acts, or encourage others to do the same, can and will be prosecuted."