The London Mayor promised a zero-tolerance stance towards social media abuse

Just six internet trolls have been brought to justice by a £1.7million 'Twitter squad' set up by London's Labour mayor Sadiq Khan.

He promised a zero-tolerance stance towards abuse on social media when the police unit was launched more than two years ago.

But the Online Hate Crime Hub – staffed by five Scotland Yard officers including a senior detective – led to just a handful of successful prosecutions, The Mail on Sunday can reveal.

Not one of the trolls was jailed.

Last night London Police and Crime Committee member Susan Hall called it an 'exercise in spin over substance'.

She added: 'This is money that could have been used to invest in additional police officers and protect Londoners from a whole host of crimes.'

We first revealed three years ago how the Met was setting up Britain's first unit dedicated to investigating offensive online comments, prompting critics to dub it 'the thought police'.

None of the six trolls prosecuted were jailed despite being found guilty of racist, anti-Semitic and homophobic posts (stock image)

It was given £1.7million in public money – more than £450,000 from the Home Office and the rest from Scotland Yard's stretched budget.

City Hall confirmed that officers dealt with 1,612 cases – about two a day – over the two years the project ran for from April 2017.

But just nine offenders were charged during the 12 months the unit was fully operational – and only six cases led to successful prosecutions.

These include trolls found guilty of racist, anti-Semitic and homophobic posts.

One offender was given a suspended jail sentence, but the rest escaped with community orders, fines and a restraining order.

Insiders partly blamed the difficulty in getting data from US-based social media firms.

A spokesman for Mr Khan said the hub helped 'support victims', adding: 'The Met has made huge progress in tackling all forms of hate crime but it's clear more needs to be done.'