More than 115,000 postal workers are to stage a series of strikes in the coming weeks in a dispute over pay.
The Communication Workers Union (CWU) said it will be the biggest strike of the summer so far to demand a “dignified, proper pay rise”.
Strikes will be held on Friday, August 26, Wednesday, 31, and September 8 and 9.
The decision follows a recent ballot for strike action, which saw members vote by 97.6% on a 77% turnout to take action.
The union said management responded by imposing a 2% pay rise, which it believed would lead to a “dramatic reduction” in workers’ living standards because of soaring inflation.
CWU general secretary Dave Ward said: “Nobody takes the decision to strike lightly, but postal workers are being pushed to the brink.
“There can be no doubt that postal workers are completely united in their determination to secure the dignified, proper pay rise they deserve.
“We can’t keep on living in a country where bosses rake in billions in profit while their employees are forced to use food banks.
“When Royal Mail bosses are raking in £758 million in profit and shareholders pocketing £400 million, our members won’t accept pleads of poverty from the company.
“Postal workers won’t meekly accept their living standards being hammered by greedy business leaders who are completely out of touch with modern Britain.
“They are sick of corporate failure getting rewarded again and again.
“The CWU’s message to Royal Mail’s leadership is simple – there will be serious disruption until you get real on pay.”
CWU deputy general secretary Terry Pullinger said: “Our members know full well what they are worth.
“They are willing to fight for a no-strings, real-terms pay rise that they are fully entitled to.
“No worker wants to be in this position, and since this dispute began, we eagerly pursued discussions and negotiations.
“But this was rejected by management, who have left us with no choice but to fight.
“Our members deserve a pay rise that rewards their fantastic achievements in keeping the country connected during the pandemic, but also helps them keep up during this current economic crisis.
“We won’t be backing down until we get just that.”
Ricky McAulay, operations director at Royal Mail said: “After more than three months of talks, the CWU have failed to engage in any meaningful discussion on the changes we need to modernise, or to come up with alternative ideas.
“The CWU rejected our offer worth up to 5.5% for CWU grade colleagues, the biggest increase we have offered for many years.
“In a business that is currently losing £1 million pounds a day, we can only fund this offer by agreeing the changes that will pay for it.
“Royal Mail can have a bright future, but we can’t achieve that by living in the past.
“By modernising we can offer more of what our customers want at a price they are willing to pay, all whilst protecting jobs on the best terms and conditions in our industry.
“The CWU’s failure to engage on the changes we need is an abdication of responsibility for the long-term job security of their members.
“We apologise to our customers for the disruption that CWU’s industrial action will cause.
“We are ready to talk further with CWU to try and avert damaging industrial action but, as we have consistently said, it must be about both change and pay.
“We have contingency plans in place, and will be working hard to minimise disruption and get our services back to normal as soon as we can to keep people, businesses and the country connected.”