Santander has cited “changes in how customers are choosing to carry out their banking” as the reason behind 140 branch closures across the UK.
The move will affect around 1,270 jobs, although the bank said it will seek to find alternative roles for those colleagues.
The number of transactions carried out through Santander branches has fallen by 23 percent over the past three years, the bank said, while transactions via digital channels have grown by 99 percent over the same period.
It added that it expects to be able to “redeploy” around a third of those affected and will be “closely supporting colleagues” over the coming weeks as the consultation process continues.
The bank said its future branch network will be made up of a combination of larger branches offering improved community facilities to support local businesses and customers, and smaller branches using the latest technology to offer customers more convenient access to banking services.
Santander will retain a nationwide network of 614 branches following the proposed changes.
Alongside the closures, 100 Santander branches will be refurbished over the next two years through an investment of £55m. The refurbishments will include a range of changes with a focus on personal service, convenience and community engagement.
Susan Allen, head of retail and business banking, said: “The way our customers are choosing to bank with us has changed dramatically in recent years, with more and more customers using online and mobile channels. As a result, we have had to take some very difficult decisions over our less visited branches, and those where we have other branches in close proximity.
"We will support customers of closing branches to find alternative ways to bank with us that best suit their individual needs. We are also working alongside our unions to support colleagues through these changes and to find alternative roles for those impacted wherever possible."