Are digital currencies, such as Bitcoin, a passing fad or are we seeing the birth of a serious currency alternative. Three foreign exchange and technology experts give us their opinions.
Steven Englander, Head of G10 FX Strategy at Citibank, thinks we need to take crypto-currencies seriously, but not as a currency. He says they have value in terms of payments and making money transfers but the thought that Bitcoin, for example, is going to be a store of value or an alternative asset is overstated. 
Sean Park, from the Anthemis Group, is less sceptical. He suggests we could see a day when exchanges or a banks are usurped. 
At the moment, there are problems with liquidity and trust, hampering the development of crypto-currencies. However, David Birch, who's a leading expert on digital money from Consult Hyperion, says the technology is improving at an amazing speed. He suggests we haven't even thought yet of how these currencies could be used in the future.