Royal Mail bosses have been accused of telling staff to deliver parcels instead of letters and Christmas cards.
The Communication Workers Union claims managers have issued instructions to “suspend delivery of letters this week”.
A letter from CWU assistant secretary Mark Baulch says staff have instead been told to “only focus on the delivery of parcels, tracked items and special delivery”.
The alleged guidance could have resulted in long delays in Christmas cards arriving from family and friends.
It came as 115,000 postal workers began the latest 48-hour strike today, which will cripple deliveries on Christmas Eve and lead to backlogs in sorting offices.
Dave Ward, general secretary of the CWU, said: “In one move Royal Mail has shown exactly why our members are striking. We want to save daily deliveries and they want to end them.
"Postal workers are striking not only to save their jobs but the service as well.”
Royal Mail said it “does not operate a policy of prioritising parcels”.
But it added: “At particularly busy times, such as in the recovery days after a strike, we may occasionally at a local level clear parcels to free up space and address health and safety concerns so that we can keep all mail, including letters, moving efficiently.”
The claims emerged as a letter to staff from Royal Mail chief executive Simon Thompson and eight senior managers said: “We are now fighting for the life of this business.”
In it, Mr Thompson said politicians and regulator Ofcom would not come to the aid of the company in the face of competition from rival couriers.
