“The holy grail of cross-border payments is a solution allowing cross-border payments to be immediate, cheap, universal and settled in a secure settlement medium,” said the study, which was co-authored by Ulrich Bindseil, the ECB's director-general for market infrastructure and payments.

“Bitcoin is least credible” of the visions to achieve that, the report continued, and stablecoins – crypto assets that seek to tie their value to other assets such as fiat currencies – come in a close second given concerns over their market power.

The report says a bitcoin-based system wouldn’t work because of its “inherently inefficient” proof-of-work consensus mechanism, the “widespread” use for criminal purposes and the volatility of the asset. It also described the fervor of the cryptocurrency’s supporters as “quasi-religious.”

There’s more mileage in linking together individual jurisdictions’ central bank-issued digital currencies (CBDCs), Bindseil wrote. although few CBDCs exist yet.

Those developing CBDCs – presumably including the ECB, which is considering a digital euro – should “discuss at a relatively early stage the related interoperability issues” to ensure they can work together with other currency zones, the study said.

They should also try to make existing domestic instant-payment systems operate with each other, despite questions over how to vet dirty money, and deal with counterparties who might default, it added.