Almost 250 jobs are to be cut by the Royal Bank of Scotland in a move described as "devastating" for affected staff.
The bank said it will ensure that compulsory redundancies will be kept to a minimum when the jobs go from sites in London and Hornchurch in Essex.
Unite said the cuts were "unnecessary and avoidable", adding that work done at the offices were still needed.
National officer Dominic Hook said: "Staff will be recruited in other parts of the country in order to do the work currently undertaken at these sites.
"While RBS state that they are committed to identifying redeployment opportunities, these do not appear to be viable geographical alternatives."
RBS said: "This is clearly difficult news for staff affected by these changes. We will do everything we can to support them, including seeking redeployment opportunities wherever possible and ensuring that compulsory redundancies are kept to a minimum."