A senior executive at the UK's financial watchdog has said the public should be warned they could lose vast amounts of money trading in digital currencies - advice that comes as new initiatives open up virtual money to a wider audience.

Chris Woolard, the Financial Conduct Authority’s executive director of strategy and competition, was speaking at a blockchain event held by at the regulator’s office last week. He said that while there is a lot of trading in bitcoin, "that’s not to say that we don’t see risks".