Detectives investigating extreme right-wing, Islamophobic and anti-Semitic postings on social media have arrested a man.

The 41-year-old was held in London on Wednesday morning on suspicion of inciting racial hatred.

Scotland Yard said the man, who is from London, was arrested at approximately 6.30am as part of a pre-planned operation in north London by officers from the Crime Disruption Unit within the the force's Counter Terrorism Command, supported by the Territorial Support Group.

A Met Police spokesman said: "Detectives executed search warrants at two addresses, both in north London, as part of this investigation, which relates to social media postings of an extreme right wing, Islamophobic and anti-Semitic nature.

"Searches at one of the addresses are ongoing. A number of digital items have been seized at one of the properties."

The arrested man has been taken to a north London police station where he remains in custody.

Meanwhile, a 20-year-old man remains in police custody for questioning after a US Army veteran was racially abused on a tram.

A 16-year-old boy and a second man, aged 18, were both bailed after also being arrested on suspicion of affray following the incident.

Juan Jasso was targeted by three youths as shocked commuters looked on during the incident on a tram in Manchester city centre on Tuesday morning.

The sport lecturer at Manchester Metropolitan University and rugby league coach has spoken of how he decided to confront the rowdy passengers for using bad language.

He said Brexit "maybe has pushed people to somehow justify that they think it's OK now to act out in this way".

Footage taken by a fellow commuter shows one youth telling Mr Jasso: "Don't chat s*** when you're not even from England, you little f****** immigrant. Get off the f****** tram now. Get back to Africa."

One of the youths, who all appear to be holding bottles of beer, then approaches and flicks alcohol from the bottle at his victim.

As the youths get off, Mr Jasso says: "Seven years in the military", as other commuters tell the three: "You are an absolute disgrace. A disgrace to England."

The youths walk away shouting: "Salford! F****** immigrant!"

On Wednesday David Cameron said extra cash for security measures will be available as part of a fresh push to drive hate crimes out of Britain.

The Prime Minister told the Commons a new action plan on the issue will be published soon.