About 750 workers are to be laid off as Bank of Scotland Ireland closes its Irish Halifax operation in a massive blow to the country's financial sector.
The company's high street retail division is to shut all 44 branches in the Republic because of the recession.
Bank of Scotland Ireland said a business review found the bank had to alter dramatically to reflect the very difficult economic environment.
Chief executive Joe Higgins said management deeply regretted the decision to shut down part of its operation.
"We have arrived at this difficult position only after an extensive and exhaustive review of all options to secure a viable future for the bank overall and for these businesses," he said.
Mr Higgins also explained the bank would be focusing purely on corporate and commercial banking in Ireland.
"It is our greatest area of expertise and one which has a deep and developed customer base. To focus on this business is the right strategy for the company and all stakeholders," he said.
Most of the affected bank workers are facing redundancy from May.
Bank of Scotland Ireland insisted customers do not need to do anything and all their savings and investments remain secure.
Management is to begin writing to customers at the end of February to explain the huge cutbacks.
A customer call centre in Dundalk, Co Louth is also being closed.
The Unite trade union said it would fight the closures and job losses.
Bernard Daly, secretary of the union's group in the bank, said workers who were notified on a conference call with the chief executive were shocked and angered.
"Our workforce is made up of partners; of people who left secure jobs on the promise of a long stable future; and of many returning sons and daughters who took the opportunity to return to Ireland and reunite their families," Mr Daly said.
"There is a huge human cost to the announcement today, and people are in a state of total shock."
It is understood the 750 redundancies include 400 Halifax branch staff, 130 call centre workers and 220 employees at the bank's Dublin headquarters on St Stephen's Green.
© Press Association