Post Office managers will stage their first industrial action in 34 years today in a dispute over pay.
The union Unite have accused the Post Office of dragging their feet for 16 months over pay discussions.
They will ban overtime and work to rule for 24 hours.
The Post Office says it remains committed to reaching an agreement with the union.
Unite have warned that further industrial action will take place if the dispute is not resolved.
National officer Brian Scott said, "Unite members will not undertake any overtime, will refuse to work any additional hours or do work not proper to their role in the organisation."