Barclays is cutting almost three hundred UK back office jobs and sending the roles to India.
The Barclaycard back-office and call centre roles are currently based in Northampton and Teesside.
A total of 285 UK workers will be affected. The bank said some new jobs will be created, with 30 in Northampton.
The offshoring exercise is intended to cut costs.
"The proposed changes are being made as part of Barclaycard's ongoing programme of improving day-to-day operational efficiency so that it can re-invest in continuing to deliver good value products and innovative services to its customers."
Rob MacGregor, Unite national officer, said: "The news that Barclays is to cut 285 staff and send the work they do abroad will devastate its workforce. This decision comes just one week after Barclays slashed another 1,000 jobs. At this time of economic uncertainty, why isn't this UK finance company doing all it can support its workforce in the UK, not telling them their work will now be done in India."
"Unite will now be challenging Barclays to ensure that the bank offers redeployment opportunities for all those impacted by the decision today," added Rob MacGregor.