Google is to ban cryptocurrency adverts following a similar move by Facebook that sees the two giants of online advertising blocking controversial cryptocurrency promotions.

Cryptocurrencies like Bitcoin are unregulated and many adverts promoting Bitcoin are misleading or scams. Google's ban will cover Google's Ad Words advertising products and YouTube, blocking adverts on cryptocurrencies including so-called initial coin offerings (ICOs).

Adverts promoting cryptocurrency and ICOs, which see people buying volatile tokens in the hope they will go up in value, have spread following the surge in interest in Bitcoin in 2017.

Many adverts appear to be scams, offering get-rich-quick schemes or encouraging people to invest in risky and unregulated ICOs, many of which have failed or even vanished with investor money. The price of Bitcoin fell around $400 this morning to $8,895, according to CoinDesk.

From June, advertisers will be blocked from posting adverts on several other controversial financial products. "This year, we updated several policies to address ads in unregulated or speculative financial products," said Google director sustainable ads Scott Spencer.