A British caver who helped rescue 12 boys from a Thai cave said yesterday he may take legal action against Elon Musk after the entrepreneur called him a "pedo."

Tesla chief executive Musk launched the tirade against Vernon Unsworth without providing any justification or explanation, after the cave expert slammed his offer of a miniature submarine to extract the footballers from the Tham Luang cave as a "PR stunt."

The "Wild Boar" team were rescued last week by an international team of divers through a narrow network of twisting, flooded tunnels.

Unsworth, who provided mapping knowledge of the cave to rescuers, said Musk's prototype would have had "absolutely no chance of working."

Musk responded on Sunday in a bizarre series of tweets referring to Unsworth, without using his name, as "pedo guy." Pedo is short for pedophile.

The entrepreneur doubled down on his claim, tweeting from his official account to more than 22 million followers: "Bet ya a signed dollar it's true."

Musk later deleted the tweets and did not respond to a request for comment.

Asked if he would take legal action against Musk over the allegation, Unsworth said: "If it's what I think it is, yes." The caver said he would make a decision when he flies back to Britain this week, but added that the episode with Musk "ain't finished."

Musk had proposed using "a tiny, kid-size submarine" featuring technology from his space exploration firm to save the boys.