The Bank of England has warned Facebook that its global digital currency Libra must meet the "highest standards" if it is to be allowed in the UK.
The Bank's financial policy committee (FPC), which is tasked with identifying potential risks in the financial system, set out rules of engagement on cryptocurrencies during a wide-ranging meeting that also covered Brexit preparations.
Minutes showed policymakers remained concerned about "entrenched" uncertainty over the UK's departure from the EU and the damage that was inflicting on the economy.
While the FPC maintained its position that the UK banking system was ready to withstand a no-deal Brexit, it said EU authorities still had work to do to prevent disruption to cross-border financial services in that event.
Its verdict on Libra was the most comprehensive to date and was released just a day after European authorities announced plans to draw up new rules for digital currency payment services.
The Bank said it was planning to apply existing regulations to Libra for now but warned that "the terms of engagement for innovations such as Libra must be adopted in advance of any launch".