Elon Musk has ramped up his row with the UK as he questioned if it was “Britain or the Soviet Union” after a man was apparently arrested over comments he made on Facebook.

The billionaire owner of X has been engaged in a war of words with Sir Keir Starmer over riots gripping the UK, amid concerns online disinformation is fuelling the unrest.

Riots latest: 30 new rallies on police radar and lawyers’ offices threatened

In his latest rebuke, Musk retweeted a video appearing to show police officers arresting a man for making offensive comments on Facebook.

He said: “Arrested for making comments on Facebook!

“Is this Britain or the Soviet Union? Is this accurate @Community Notes.”

Community Notes is X’s own fact checking resource.

In the video, the man is arrested on suspicion of improper use of the electronics communications network.

This covers things like sending a message that is “grossly offensive or of an indecent, obscene or menacing character” and can result in a maximum six month jail term or a fine.

In another tweet on Tuesday afternoon aimed directly at Sir Keir, Musk asked “why aren’t all communities protected in Britain?”.

It was in response to a video appearing to show large crowds of masked people gathered outside a pub, some waving the Palestine flag.

Musk directed a similar comment towards the the prime minister yesterday, after Sir Keir said he would not tolerate attacks on Muslim communities.

Mosques and hotels housing asylum seekers have been among the targets of unrest across the UK for the past week.

The tech billionaire has also claimed that “civil war is inevitable” in the UK – comments which have been condemned by Downing Street and justice minister Heidi Alexander.

Ms Alexander earlier told Sky News that “everyone should be calling for calm in this situation”.

“So I do think the language around civil war being inevitable is totally unjustified,” she added.

The riots began in Southport last Tuesday in the wake of the fatal stabbings of three girls in the Merseyside town, and have spread to towns and cities across the UK.

The row risks threatening government efforts to get social media companies to take more responsibility for removing harmful online content believed to be stoking some of the violence.

Misinformation online said the person arrested, 17-year-old Axel Rudakubana, was a Muslim refugee who arrived in the UK last year via a small boat.

Rudakubana was born in Cardiff to Rwandan parents before moving to a village near Southport.

Sir Keir has been clear that anyone inciting violence – whether online or offline – “will face the full force of the law”.

Former police chief Neil Basu has said the worst of the far-right violence should be treated as terrorism.