Elon Musk has launched an astonishing and unsubstantiated attack on the British diver who led the rescue of 12 boys and their football coach from a flooded cave in Thailand.

Musk baselessly branded expat Vernon Unsworth a paedophile after he dismissed a mini-submarine the billionaire’s team built for the rescue effort as a “PR stunt.”

In an interview with CNN, Unsworth said: “It just had absolutely no chance of working. He had no conception of what the cave passage was like. The submarine, I believe, was about 5ft 6in long, rigid, so it wouldn’t have gone round corners or any obstacles.”

The 63-year-old, who has expert local knowledge of the Tham Luang cave system, added Musk could “stick his submarine where it hurts.”

The children were eventually rescued individually, each accompanied by two divers and navigating dark and tight passageways filled with muddy water and strong currents, as well as oxygen-depleted air. 

In a string of bizarre, now deleted tweets, Musk said he was working on producing a video to prove his submarine could have reached the children. “Sorry pedo guy, you really did ask for it,” he tweeted to his 22.3million followers.

He also inferred it was “suspicious” that Unsworth lives in Thailand and when challenged on his allegations, continued: “bet ya a signed dollar it’s true.”

Unsworth has since responded to the matter, telling the Guardian: “I believe he’s called me a paedophile. I think people realise what sort of guy [Musk] is.”

When asked if he would consider taking legal action against Musk, Unsworth replied: “Yes, it’s not finished.”

BBC reporter Jonathan Head defended Unsworth, tweeting at Musk an account of his herculean efforts and concluding: “It’s somewhere between extremely probable and almost certain that the 13 would have died trapped in Tham Luang without Unsworth’s role.”