A new Scotland Yard police unit which will investigate online hate crime has been launched by Mayor Sadiq Khan.

The five strong unit - the first of its kind in the UK - will aim to gather intelligence on online abusers on sites such as Twitter and Facebook as well as improving support for victims.

The £1.7m unit, first announced last year, will be partially funded by the Home Office to tackle the rise in online hate crimes.

While only between two and five per cent of hate crimes reported to the Met are online, community groups say the number of offences may be much higher and hugely under reported.

The Jewish organisation, Community Security Trust, says around 20 per cent of cases are online and Tell MAMA, which measures Islamaphobic hate offences, estimates that over 70 per cent of the reports it receives are online cases.

Mr Khan, said: “We know hate crime has a huge impact on those who experience it, and that online hate, where abusers mistakenly believe they are hidden behind a screen, can be particularly damaging.

“My approach is clear: there must be zero tolerance of this behaviour, and we are working to improve protection for victims by taking advice from anti-hate organisations, who will examine whether something is actively causing harm and should be removed.”

The so-called OnLine Hate Crime Hub will gather intelligence on Twitter trolls and other abusers and hand cases to borough police officers to investigate.

The creation of the unit comes after a series of a court cases in which Twitter trolls have been jailed for sending abusive messages to MPs and other high profile figures.

Anti-Brexit campaigner Gina Miller has told how she has faced repeated abuse online, including threats that she would be “the next Jo Cox,” the MP murdered by an extremist fanatic. The Met has made several arrests.