The Bank for International Settlements has come down hard on cryptocurrencies in its forthcoming annual report, declaring that they are usesless as a medium of exchange and have no intrinsic value.

The Swiss-based “bank of central bankers” cited high transation costs, slow transaction times and the large carbon footprint created by miners, which reportedly consume as much electricity as Switzerland.

The bank claims cryptocurrencies, which are not backed by established states, are merely Ponzi schemes purporting to be citizen currencies that can quickly become worthless due to fraud or digital tampering.

The report said: “Trust can evaporate at any time because of the fragility of the decentralized consensus through which transactions are recorded. A cryptocurrency can simply stop functioning, resulting in a complete loss of value.”