London continues to compete with San Francisco's web expertise and New York's financial clout as it pushes to be the foremost financial technology - or fintech - center in the world. Already a center of the $5-trillion-a-day global currency market, it now wants to be home to a controversial upstart –bitcoin.

British authorities have recently come out in support of digital currencies in the name of promoting financial innovation, while proposing that regulations should be drawn up to prevent their use in crime.

The effort has been galvanized by technophiles, such as the 2,200-member group, CoinScrum, who are leading the drive to make London a hub for trade in web-based "cryptocurrencies", of which bitcoin is the original and still most popular.

CoinScrum, run by a former derivatives trader who left the world of traditional finance to work on a digital currency start-up, is the biggest bitcoin networking group in the world. It meets every Tuesday evening and attracts a motley group of amateurs and others eager to start bitcoin businesses in Britain.

Prevent Money-Laundering

The British government announced plans last month to regulate digital currency exchanges to prevent their use in money-laundering, and to help to develop a set of standards for cryptocurrencies.

Backers of bitcoin praised this for lending legitimacy to the currency - which unlike traditional money has no printed form and remains outside the control of central banks - without stifling innovation.

"London has been the home of financial innovation for hundreds of years," said Nicolas Cary, co-founder of Blockchain, which provides bitcoin data and "wallet" software for storing the currency. "It would be a historical mistake not to make this the home of digital currencies. There's an incredible amount of talent and experience here."

Just over 14 million bitcoins are in circulation, worth around $3.1 billion at the current exchange rate of around $220 each.