Royal Mail workers will stage fresh strikes in the days before Christmas in the increasingly bitter dispute over jobs, pay and conditions.
Members of the Communication Workers Union (CWU) will walk out on Friday and Christmas Eve following a spate of stoppages this year.
The company said it will be doing all it can to deliver Christmas mail, revealing that the industrial action has cost it £100 million.
A Royal Mail spokesperson said: “Thousands of employees from across the business have swapped their regular day jobs to help sort and deliver the festive mail bag.
“We are grateful to them and the more than 12,000 posties who returned to work on the last strike day. Their huge efforts will ensure we deliver as many letters and parcels as possible for Christmas.
“The targeting of six days of strike action in December by the CWU is a cynical attempt to hold Christmas to ransom.
“We apologise for any disruption and uncertainty caused to customers, businesses and families across the country as a result of the CWU’s strike action.
“We urge the CWU to seriously consider our pay offer of up to 9%, and to work with us to bring the company back to profitability. Royal Mail is not too big to fail.
“The company’s future and all our employees’ jobs depend on Royal Mail modernising so that we can better serve customers’ changing demands. That is in the best interests of Royal Mail, its employees and its customers.”
The CWU has accused Royal Mail of refusing an offer to suspend the strikes and establish a period of calm until January 16.
CWU General Secretary Dave Ward said: “For Royal Mail Group to reject our offer just hours after receiving it demonstrates that they were never serious about saving Christmas for customers and businesses.
“When a company openly boasts of having built a £1.7 billion fund to crush its own workers rather than use that money to settle the dispute and restore the service, then you know dark forces are clearly at work.
“Their sole intention is to destroy the jobs of postal workers and remove their union from the workplace.
“Our members will not stand for this, and further action will take place in 2023.
“Our message to the public and businesses is that postal workers do not want to be here, but they are facing an aggressive, reckless and out-of-control chief executive committed to wrecking their livelihoods.”
