Royal Bank of Scotland is shutting 259 branches, one in four of its physical offices, and making 680 people redundant.
The firm says more customers bank online, reducing remand for face-to-face services.
RBS is closing 62 branches and NatWest 197. The banking group will have 744 branches left after the changes take place in late May and early June next year.
An RBS spokesperson has been approached for comment.
Unite the union slated the news.
Unite national officer Rob MacGregor says: “The Royal Bank of Scotland has decided to decimate its bank branch network. Now serious questions need to be asked about whether these closures mark the end of branch network banking.
“The closure of another 259 branches is savage and represents a betrayal of loyal staff and customers who have supported the bank for decades. Why is the Government signing off this alarming branch closure program?”