The planned inclusion of iris scanning for authentication in a mobile banking app is in itself interesting, but it's how that is possible for TSB that is worth a bit further analysis. 

TSB was purchased by Sabadell which completed 8 July 2015, just two years ago. Since then there has a focus on setting up the infrastructure to support an agile digital delivery using a UK version of their Proteo4UK platform. There was quite a bit of concern at the purchase time as to the IT risk of migrating to the platform. This was built in 2000 to support mergers of which there have been approximately 13 in their history - indicating quite a pedigree in integrating different underlying systems. Their mobile app press release also references preparation for future open banking initiatives. 

All evidence that the delivery of a service like iris scanning is likely not to be a one off bolt on service, but reflecting investment and focus on the underlying digital foundations.