In the week that Vladimir Putin weighed in and opined that cryptocurrencies need to be regulated, and research revealed that bitcoins jump from $150 to $1,000 was likely caused by one person, all major cryptocurrencies saw drops in value. Bitcoin fell below $10,000 (it has been nearing $20,000 in December), and the cryptocurrency market has lost around $340bn since the start of the month, according to data from CoinMarketCap.

Most analysts are putting the sell-off down to fears of a regulatory crackdown, particularly in Asia, which is where the lion’s share of crypto-trading goes on. South Korea and China are tightening already stringent regulations. Meanwhile, a director at Germany’s central bank has said it’s not possible to regulate cryptocurrencies on a regional or national scale – regulation would have to be global.

Closer to home, UK mortgage lenders and brokers are rejecting applications from crypto investors, on the grounds that they can’t trace the source of the money. There are also claims being made that some banks (and this isn’t in the UK but is in the West) are blocking transactions related to digital currencies.

If a currency is banned, you can’t use it. You also can’t use it if regulation, or the threat of regulation, wipes out its value. States have the power to make stores of value valueless. It’s important that sensible conversations around regulation progress to a level of clarity and certainty, otherwise this toppy market will never be more than a speculator’s heaven.

And expect the banks to become increasingly draconian; cryptocurrencies pose an existential threat.