Tens of thousands of postal workers are to be balloted on strike action after pay negotiations between unions and management broke down.
The Communication Workers Union (CWU) will send ballot papers out to its 136,000 members by 10 July.
The union said the move followed the imposition of a 2.9% pay rise (plus 1% related to productivity), and the failure to reach a deal on plans to axe thousands of jobs.
The Royal Mail said it was willing to hold talks, but faced a huge challenge to modernise the business.
Hopes remain of reaching a settlement after the CWU confirmed its willingness to resolve the dispute through negotiations.
CWU deputy general secretary Dave Ward told the BBC that the delay in sending out papers was intended to allow time to reach agreement and “get a resolution”.
The Royal Mail’s plans include issuing workers with a 20% share in the company. But the union fears this could mean 40,000 of the organisation’s 165,000 workers losing their jobs, with many other workers forced to work part-time.