Facebook’s proposed libra digital coin must show it is “rock solid” before it can be allowed to launch, Bank of England governor Mark Carney said. Photograph: Dado Ruvic/Reuters

(...) bankers’s comments have knocked cryptocurrencies, with most losing between 7 and 8 per cent of their value(...)

Mining cryptocurrencies is consuming as much electricity as a G20 economy, IMF  managing director Christine Lagarde has said in Davos. Photograph: Denis Balibouse/Reuters

The risk that cryptocurrencies can be used by criminals means Britain and other governments should(...)