FinTech firm Revolut has become the first digital bank to break even on a monthly basis thanks to a rocketing user base.

London-based Revolut had 1.5 million users across Europe in December, up 50 per cent on a month previously.

It began life in 2015 as a cheap currency exchange product linked to an app and expanded to include a suite of other services such as travel and device insurance, while also allowing people to buy, hold and sell cryptocurrencies within the app.

"Instead of becoming a bank from day one, we chose to focus our time and resources on product development and customer acquisition,” said co-founder and CEO Nikolay Storonsky.

“This strategy is clearly paying off as we are have now firmly positioned ourselves as the market leader in Europe and soon the world."

Revolut, which is in the process of securing a banking licence, saw rapid growth around Europe and has plans to expand to India, Brazil, South Africa and the UAE.

It now has 350,000 daily active users and more than 800,000 monthly active users. It is signing them up at a rate of 6,000- 8,000 a day.

It said its monthly transaction volume is now $1.5 billion, having processed $10bn of transactions to date.

Revolut has raised $90 million in funding to date. Competitors such as Monzo, Starling Bank, Tandem and Atom are all loss-making, Reuters reported.

OakNorth was the first challenger bank in the UK to report an annual profit.

CORRECTION: We have amended this article to specify that Revolut broke even on a monthly basis and also that OakNorth was the first challenger bank in the UK to report an annual profit.