Christmas postal deliveries in London could be hit if union members vote to take industrial action over pay.
The Communication Workers Union (CWU) is calling for strikes in a row over overtime needed to clear the increase in post in the run-up to the festive holidays.
The union also claimed workers were being forced to work on their days off. A spokesman said: “Everyone knows our members will be weighed down like pack mules this Christmas, but Royal Mail is not willing to pay the rate for delivering the work.
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“Unfortunately, it looks like we’re heading for very serious problems over Christmas.”
The Royal Mail said the CWU was asking for extra pay for overtime that may not be needed.