As a commercial project, Facebook’s digital currency proposal is flailing, having lost partners and failed to charm regulators. But at the IMF’s annual meeting in Washington last week it was clear that Libra had already notched up one success: it had spooked central bankers.

When he announced Libra in June, Mark Zuckerberg let slip to policymakers they were already behind in a race they did not know they were running. They have now got the message: if they do not have a hard think about whe-ther to make their own digital monies, someone else will.

Two years ago Stefan Ingves, governor of Sweden’s central bank, started looking into an e-krona to be created and run by the Riksbank. At the time, his colleagues in other countries were bemused but over the summer, said Mr Ingves, “we ended up in a lot of conversations about Libra, because Libra showed up, at least from a central bank perspective, kind of out of the blue”.