Mr Brown will join as CEO designate next Wednesday and will work with outgoing CEO Peter Griffiths for a short handover period.

During his time with the Royal Bank of Scotland group, Mr Brown was CEO of Williams and Glyn from 2015 to 2017, CEO of Ulster Bank from 2011 to 2015, and chief executive of retail and commercial markets for RBS Asia from 2005 to 2011.

Mike Coupe, CEO of Sainsbury’s, said: “Jim has a wealth of experience and a strong track record of leading banks through significant change, which will help him lead Sainsbury’s Bank through the next stage of its journey. I am delighted to welcome Jim to the Sainsbury’s management team.”

Mr Brown said: “I’m really excited to be joining Sainsbury’s, which has a very strong brand and is well trusted by its customers. The combination of Sainsbury’s, Argos and Nectar, along with Sainsbury’s Bank, provides a real and unique opportunity to offer customers easy access to digitally-led financial services.

“I have been impressed by everyone I have met so far and am very much looking forward to joining the team.”