Fujitsu Services has announced proposals to close its final salary pension scheme in order to reduce risk.
The computer services company closed the defined benefit (DB) scheme to new joiners in 2000, but now intends to close it to future accrual for existing members.
A spokesman for Fujitsu Services said: "Whilst this action is regretted it is a prudent step to enable us to manage the pension risk."
The firm will now consult with 4,000 of its 14,500 staff who are still members of the scheme, along with the trade union, Unite.
Peter Skyte, Unite national officer, said: “Fujitsu Services is a highly profitable company and made £177 million profit in the last financial year.
“The company has yet to produce any proper justification for this latest attempt to raise profits by cutting pension benefits, and this action may hinder future bids for blue chip private sector outsourcing contracts.
“We will be mounting a robust campaign to persuade the company to think again.”