Yorkshire Building Society Group will pull its Norwich & Peterborough brand this year as part of an overhaul that will see nearly 50 branches shut.
YBSG says it will close 20 Yorkshire Building Society branches in May and 28 N&P branches from September.
The society plans to close its N&P current accounts to existing customers and withdraw the N&P brand from the high street over the next year.
YBSG says the changes will give better value to its 3.3 million customers.
A YBSG statement says: “The proposals would enable the mutual to increase focus on one high street brand and continue to invest in its core mortgages and savings businesses, making its services as easy and simple as possible for customers.”
The group says it will keep a high street network of 260 branches and agencies across the UK, with Yorkshire Building Society as the sole high street brand.
The society says it will contact affected customers to discuss their options.
Yorkshire Building Society chief executive Mike Regnier says: “As a mutual, it is important that we always act in the best long-term interests of our membership and evolve the business in line with their changing needs.
“We believe these proposals give us greater focus on providing existing and future members with the things they want from us most: a safe place for their savings and funding to buy their own home, and providing these in an easy and simple way.”
“We continually review all areas of the business to ensure we remain focused on what our members require while utilising their money as effectively as possible. This means we must sometimes make adjustments to the way the business operates.”
Regnier says the main forces behind the branch closures are “shifts in market conditions and an increasing desire among customers to transact digitally rather than on the high street”.
He says: “We therefore no longer believe it is the right commercial position for us to continue to maintain these 48 branches across the N&P and Yorkshire network.”
Regnier adds that continuing to provide current accounts would be too expensive.
He says: “The Norwich & Peterborough brand has been part of Yorkshire Building Society since 2011, and inevitably, some of our colleagues and members will be disappointed by these proposals.
“The values of the N&P and Yorkshire brands are synonymous and we believe operating with Yorkshire Building Society as our sole high street brand would allow us to run the business more effectively and efficiently, enabling us to deliver better products and services for our members.”