At 11am, Bitcoin was priced at $39,416. Musk tweeted at 12.07 and by 1.30pm it had dropped to $38,774 - a 1.63 percent drop in just over an hour. Ethereum fell 2.2 percent from $2,442 to $2,388 during the same period. And meme coin Dogecoin fell 1.9 percent from a high of $0.314 at 8.15am to a low of $0.308 at 1.15pm.

The drop in prices for the cryptocurrencies comes after Elon Musk responded to reports Bitcoin is "greener" than critics say.

The entrepreneur and business magnate hit back at Jesse Powell, chief executive of the Kraken crypto exchange, who said bitcoin is "a lot greener than people give it credit for".

Mr Powell told Bloomberg TV on Thursday that Musk has got "some more studying to do on this topic."

Responding to the statement on Twitter, Musk said: "Based on what data?"

The commment by the Tesla CEO has reignited his argument that Bitcoin is environmentally damaging due to the "insane" energy use required for the computing work that secures the network and creates new coins.

Last month, Mr Musk said his car company would stop accepting Bitcoin as a payment for its products due to concerns over how cryptocurrency mining contributes to climate change.

He said in a statement: “We are concerned about rapidly increasing use of fossil fuels for Bitcoin mining and transactions, especially coal, which has the worst emissions of any fuel."

The announcement triggered a sharp fall in the price of Bitcoin.

On Sunday Mr Must said Tesla will resume Bitcoin transactions once it confirms there is reasonable clean energy usage by miners.

He said in a Tweet: “When there’s confirmation of reasonable (-50 percent) clean energy usage by miners with positive future trend, Tesla will resume allowing bitcoin transactions."

Mr Musk’s comments on social media about cryptocurrency often send prices soaring or plummeting.

It comes as new data suggests 2.3 million adults are estimated to hold cryptocurrencies, up from 1.8 million last year, according to the City regulator.

While ownership of cryptocurrencies has increased, understanding of them appears to have decreased, according to the findings from the Financial Conduct Authority (FCA).

It has warned that investing in cryptocurrencies is high risk and investors should be prepared to lose all their money.

People have around £300 invested on average.

The FCA cryptocurrencies can take many forms and some include Bitcoin and Ripple.

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