The British caver accused by Elon Musk of being a "child rapist" is reportedly considering suing the technology billionaire in three countries as he blasted the baseless claims as “100 per cent” untrue.

The Tesla founder has escalated his feud with Vernon Unsworth, one of the divers involved in July’s rescue of a group of young Thai footballers, whom he had previously accused of being a paedophile.

On Tuesday, Buzzfeed published emails Mr Musk sent last week, in which he launched another unfounded attack on Mr Unsworth.

"I suggest that you call people you know in Thailand, find out what's actually going on and stop defending child rapists, you f------- a------," Mr Musk wrote.

“He’s an old, single white guy from England who’s been travelling to or living in Thailand for 30 to 40 years, mostly Pattaya Beach, until moving to Chiang Rai for a child bride who was about 12 years old at the time.”