National Australia Bank is to cut about 1,700 jobs at its two UK operations in a move to save £117m ($220m) a year.
NAB employs more than 10,000 people in the UK
The redundancies at the Yorkshire and Clydesdale banks will take place over the next 12 to 18 months.
NAB, which employs about 10,300 people in the UK, said the restructuring would make its businesses "more nimble and customer focused".
It plans to end job duplication, with many posts going at administrative offices in Glasgow and Leeds.
"We are committed to a strong presence in the UK, but do so we must change the way we do business," the bank said.
NAB revealed last month that it was reviewing its business in the UK, where it has 2.7 million customers.
Leeds-based Yorkshire, which has 232 branches, is expected to see about 950 job losses.
About 750 jobs will fall at Glasgow-based Clydesdale, which has 217 branches.
Some "unprofitable" branches would close as part of the restructuring, although exact locations would not be confirmed until May.
But NAB said the majority of job cuts would not affect the 4,217 staff who deal with customers.
Some of the 1,700 positions will be covered by staff turnover and there would be redeployment, it added.
"All areas of our existing operations have been under review and we are moving quickly to implement the changes necessary to create an efficient, competitive business," said the NAB's UK chief executive Lynne Peacock.
'Last bank in town'
Unions said they had received a commitment that NAB would strive to avoid compulsory redundancies through retraining and redeployment programmes.
"We will also be working to ensure that the bank operates the redeployment procedures properly and will campaign vigorously against any 'last bank in town' branch closures," said Wendy Dunsmore of Amicus.
NAB has said both the Yorkshire and Clydesdale faced falling profits, amid higher costs and declining margins, although it has forecast a turnaround by 2007.
Its UK division has recently started to push into the south of England, through the opening of 15 designated business banking centres.
The bank said about 40 existing Yorkshire and Clydesdale business banking centres in the north of England would also be coming under the same brand.
NAB, which is to take a charge of £109m in its first-half results to cover the costs of the restructuring, sold its two struggling Irish banks Northern and National Irish last year.