Internet trolls who post offensive messages or images online face prosecution under new legal guidelines

Nine people a day are being arrested for posting allegedly offensive messages online as police step up their campaign to combat social media hate speech.

More than 3,300 people were detained and questioned last year over so-called trolling on social media and other online forums, a rise of nearly 50 per cent in two years, according to figures obtained by The Times.

About half of the investigations were dropped before prosecutions were brought, however, leading to criticism from civil liberties campaigners that the authorities are over-policing the internet and threatening free speech.

Arrests are expected to rise after Amber Rudd, the home secretary, last week announced a national police hub to crack down on hateful material online. Freedom of information requests have revealed that