The Royal Mail is facing increased competition and a long term decline in one of their core businesses, delivering letters, as people switch to e-mail. Big demand for parcel services from online stores was the silver lining to that cloud. But, the company is losing key contracts from firms like Amazon.
In practice, there has been steady disruption from local strikes targetted to maximise the interruption to services for some time. The national strike may well be the straw that breaks the camel's back for many customers, though. Who will find another firm to deliver their parcels.
It will also be a huge hassle for ordinary people. Even if the union was in the right in their dispute with management, punishing customers and small businesses who depend on the service for that is deeply unfair. But, while the management may not be perfect and it is hard for those outside the process to follow the detail of the dispute, it becomes clear that the union are being far from reasonable when they do things like compare an ordinary working day, getting paid for the hours you work, to slavery.
This strike should simply be cancelled. It is going to hurt ordinary taxpayers who both own the company and depend on its service.