Post workers have come out in a new wage dispute, which could result in 114 offices being unable to open.
Members of the Communications Workers Union (CWU) at Crown post offices, the largest branches often on main streets, went on strike on Saturday.
Members of administration unions and supply chain networks will go on strike on Monday.
The union’s action assumes that there will be no cash collections or deliveries to post offices tomorrow, the union warned.
However, the Post Office said it hoped the “vast majority” of its offices would not be affected by the strike.
Image: A woman walks past a sign informing customers of the closure of a post office due to industrial action in St Albans earlier this month
The second union action has been held on Saturday since the dispute broke out and the union does not rule out new strikes.
The union said the post office is insisting on a pay freeze for 2021-22 and a “more marginally improved” salary offer for 2022.
CWU Deputy Secretary Andy Furey said: “Our members do not want to be in this situation, but they will not accept humiliation either.
“Our members worked hard to make an excellent annual profit for the company – affordability is not a management issue here.
“Frankly, their degrading excuse for an offer has only hardened members, who will not tolerate a collapse in their standard of living.
“We thank the public for their understanding and support, and urge the Post Office to turn the table around and approve a real deal that treats key working heroes with the respect they deserve.”
Some 3,500 trade unionists are involved in the dispute.
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A spokesman for the Post Office said: “We want to assure our customers that the vast majority of our offices are unaffected by the CWU strike on Saturday.
“There are 114 offices, usually in the city center, which are managed directly by the Post Office.
“More than two-thirds would normally only be open between 9 a.m. and 12:30 p.m. on Saturdays. We apologize to customers who have trouble closing.”