Customers of the Royal Bank of Scotland (RBS) and NatWest using iPhones equipped with Touch ID will now be able to log into RBS's mobile app using their fingerprints.
It is the first time a British bank, albeit one owned mostly by the government, has rolled out biometric authentication to customers, though Barclays began offering a finger scanner to corporate customers last year.
The service, which the bank developed in response to dwindling branch business and uptick in mobile and online banking, will be available to 880,000 customers who use RBS or NatWest mobile apps on their iPhones.
RBS has said almost half of its 15 million customers now conduct their banking online with about three million a week using the bank's mobile app. RBS plans to invest $1.5 billion in mobile banking in three years.