Royal Bank of Scotland is to close 162 branches in England and Wales, resulting in 792 job losses.
The lender, still 72% owned by the taxpayer, said the move was linked to its decision not to sell its Williams & Glyn business.
As a result, the group has branches in close proximity to another and is seeking to reduce overlap.
RBS said: "Following a review of the branch network in England and Wales a decision has been taken to close 162 Royal Bank of Scotland branches.
"As a result of this process, around 792 roles will be made redundant, and we will seek to support our colleagues with the option to leave on a voluntary basis."
The closures come as RBS reintegrates Williams & Glyn, including its branch network, back into the core bank.
A total of 109 branches will close in late July and August 2018. These branches are within 0.6 miles of another Royal Bank of Scotland or NatWest branch.
A further 53 branches will close in November 2018, all of which are between 0.6 and 2.5 miles of another Royal Bank of Scotland or NatWest branch.
An RBS spokesperson said: "We are no longer launching Williams & Glyn as a challenger bank, and we now have two branch networks operating in close proximity to each other - NatWest and Royal Bank of Scotland - in England & Wales.
"As a result we have had to review our overall branch footprint in England and Wales and we've made the difficult decision to close a number of Royal Bank of Scotland branches. Customers of Royal Bank of Scotland in England & Wales will be able to use NatWest branches instead for their everyday banking needs.
"We now provide our customers with more ways to bank with us than ever before - customers can choose from a range of digital, face-to-face and local options to suit their needs."