A British diver who helped rescue 12 Thai boys from a flooded cave has criticised Elon Musk's plan to retrieve them using a mini-submarine, calling it a "PR stunt".
"He can stick his submarine where it hurts," said Vern Unsworth, 63, a Briton who lives in Thailand.
Rolling his eyes Mr Unsworth told CNN: "It just had absolutely no chance of working. They had no conception of what the cave passage was like.
"The submarine, I believe was about 5ft 6 long, rigid, so it wouldn't have gone round corners or any obstacles. It wouldn't have made the first 50 metres into the cave from the dive start point. Just a PR stunt."
Mr Musk had himself gone into the cave, but Mr Unsworh said: "...and was asked to leave very quickly, and so he should have been."
Cave rescuer on Musk: “It was a PR stunt. It had no chance of working.” pic.twitter.com/uPgRMQLkRx— Quoth the Raven (@QTRResearch) July 13, 2018
Mr Musk, the billionaire founder of Tesla and SpaceX, had built a prototype submarine as rescuers worked to free the 12 boys and their football coach.
His pod was named "Wild Boar" after their football team and he released videos of it being tested in a swimming pool in California.
It was made from parts of a rocket, could fit through small gaps, and was light enough to be carried by two divers.
All the boys and their coach were successfully rescued from the Tham Luang Cave on Tuesday without Mr Musk's help.
A leader of the operation had previously called the mini-submarine idea "not practical".
That led to Mr Musk being criticised by some people on social media.
The billionaire said he had just been trying to help.
He said: “This reaction has shaken my opinion of many people.
"We were asked to create a backup option and worked hard to do so. Checked with dive team many times to confirm it was worthwhile. Now it’s there for anyone who needs it in the future.
"Something’s messed up if this is not a good thing."