Royal Mail workers are set to strike for 48 hours from 19 October in a dispute over pensions, pay and jobs, APA reports quoting BBC.
The Communication Workers Union said it had told the Royal Mail Group that 111,000 postal workers will walk out.
The industrial action follows the 89.1% vote in favour of a strike announced by the union on Thursday.
Royal Mail said it will use all legal options, including applying for a High Court injunction, to prevent industrial action.
The FTSE 100-listed company said it was "committed to further talks as a matter of urgency to reach agreement with the CWU", adding: "There are no grounds for industrial action."
The union said the company's move to replace the pension scheme meant its members would lose up to a third of their retirement entitlements.
CWU general secretary Dave Ward said it was a "watershed dispute" that would determine the future of the postal service.
"We are determined to take whatever steps are necessary to deliver an agreement that will protect and enhance our member's terms and conditions and improve the range of services on offer to customers," he said.