Bitcoin’s price slumped on Tuesday night as Facebook announced it would ban adverts promoting cryptocurrencies and US authorities launched a probe into a large online exchange.

Facebook announced a new policy prohibiting adverts that relate to cryptocurrencies or initial coin offerings (ICOs) from the 2bn-user social network, saying they are “frequently associated with misleading or deceptive promotional practices”.

Adverts for cryptocurrency-related investments have leapt in recent months as Bitcoin prices have skyrocketed, but many are feared to be scams.

Meanwhile, it emerged that the Commodity Futures Trading Commission (CFTC) has subpoenaed Bitfinex, a popular US website for buying and selling Bitcoin, and Tether, a cryptocurrency linked to the dollar that is often used for buying Bitcoin.

Bitcoin’s price fell by more than 10pc to trade as low as $9,810 (£6,940), its lowest for two months and less than half the price it peaked at in December. The growing threat of regulation has weighed heavily on demand for cryptocurrencies in recent weeks following the extraordinary Bitcoin boom of 2017.