Gemini, the cryptocurrency exchange founded by the Winklevoss twins, is expanding into the U.K, the company said on Tuesday.

Cameron and Tyler Winklevoss launched Gemini in October after the New York State Department of Financial Services allowed it to operate in 31 U.S. states and in Washington, D.C. The company allows people to buy and sell the digital currency bitcoin and its rival ether.

In May, Gemini became the world's first licensed ether exchange. Ether is a digital currency similar to bitcoin which runs on the Ethereum blockchain. One ether is currently worth around $11.46 and it has a total market cap of around $959.1 million. Bitcoin in contrast is worth $751.89 with a market cap of $11.7 billion.

But ether is seen as a potential successor to bitcoin with the underlying Ethereum blockchain able to carry out so-called "smart contracts" – a contract that is able to execute itself when certain conditions are met. Ethereum has recently been involved with a number of banks to trial the use of its blockchain for financial transactions.

Gemini has been on an aggressive expansion path since its October launch. It has begun operations in Canada and announced its U.K. launch on Tuesday. Customers in Britain can now buy ether with bitcoin and sell ether for bitcoin. Soon, Gemini will add support for trading bitcoin and ether with U.S. dollars for U.K. and Canadian users, a feature already available to all of its U.S. customers.

But Gemini is young and lags other exchanges such as BTC China in terms of bitcoin trading volumes, something the Winklevoss twins hope to change through expansion.

"Our onboarding queue is huge, it's continued to grow … we have only been operational for about eight months now … each month has increased growth better than the next. This month we are already on track to do … a trading volume of around $100 million of U.S. dollar notional value of both bitcoin and ether … We are really young and it's a really new space and it's just the beginning but we are really encouraged with the growth and the way things have been going," Tyler Winklevoss told CNBC Tuesday.