Elon Musk will have to go to trial to defend himself for calling one of the divers who helped rescue schoolboys trapped in a Thai cave a “pedo”.

The Tesla boss tweeted the insult at British cave diver Vernon Unsworth last summer after the underwater rescue of the football players.

A federal court judge in Los Angeles set an October 22 trial date. It rejected Musk’s attempt to dismiss the defamation lawsuit filed by Unsworth.

Musk called Unsworth a “pedo” in a July 15 post to his 22 million Twitter followers, after Unsworth dismissed Musk’s attempts to help rescue the football players with a submarine as a “PR stunt”.

He later accused Unsworth of moving to Thailand to be with a bride who was about 12 years old.

Musk contended his insult was protected from legal action but the judge overseeing the case disagreed.

The lawsuit filed in Los Angeles federal court seeks more than $75,000 (£57,000) in damages and a court order stopping Musk from making further allegations.