Barclays workers are to vote on strike action over the bank's move to close its final salary pension scheme, it was announced today.
Unite said its members were "incensed" at the plans to close the scheme to existing members and revealed nine out of 10 staff had pressed for an industrial action ballot.
Voting will be held next month and Unite warned strikes could be held in September, with a "significant" impact on the bank's services.
The bank unveiled plans last month to shut its final salary scheme to existing members, affecting 17,000 staff, although 1,500 of its top earners were not affected.
Derek Simpson, joint leader of Unite, said: "It is unacceptable that Barclays are proposing this unilateral change to workers' pensions. Unite members will not stand by as their employer rides roughshod over their retirement security.
"The long-serving and dedicated workforce view this pension proposal as a betrayal by their employer. Consultation with our members has shown the depth of anger over the pension issue. Over 90% of Unite members are demanding a ballot for industrial action over this action by their employer.
"The forthcoming ballot within Barclays will send a strong message to private sector employers across the economy. Unite will not accept businesses using the economic downturn as a means to erode the important terms and conditions of our members.
"Unite has proposed viable alternatives to Barclays in order to make the cost savings they argue are essential for the pension scheme to be viable. The company has failed to engage with the union on these suggestions. We would urge them to go back to the drawing board in order to avert damaging strike action."
Unite represents more than 25,000 staff at Barclays, including workers at branches, processing centres, call centres, computer centres, Barclaycard centres and offshore Islands and Gibraltar.