The postal workers' union has threatened to continue strike action into the Christmas period unless they can reach a "fair" settlement with Post Office management.
Dave Ward, CWU deputy general secretary, said:
If the Post Office thinks this dispute will simply fade away they are sadly mistaken. The company's plans are to downgrade the network, reduce services to local communities and hit jobs in the network.
Next week's strike and the continuing sales ban activity will continue into the Christmas period unless management see sense and negotiate a fair deal for Crown office staff.
The union said next week's strike will affect up to 4,000 staff in 372 offices.
More top news
After a mild and quiet night, the best of the sunshine will be across the south east.
The presumptive Democratic Presidential candidate said Kaine is everything Donald Trump is not as they shared a platform for the first time.
Team Sky's Chris Froome is set to win the 2016 Tour de France with an overall lead of four minutes 11 seconds after stage 20 to Morzine