Royal Mail workers will stage two 48-hour strikes around Black Friday and Cyber Monday after their union rejected the company’s latest pay offer and programme for change, describing it as a “declaration of war on posties”. The Communication Workers Union (CWU), which represents Royal Mail staff, announced on Tuesday night that workers would be striking on 24 November and 25 November, known as Black Friday, the biggest shopping day of the year. Workers will start a second 48-hour strike on 30 November, two days after Cyber Monday, one of the busiest shopping days for online purchases. Many retailers run promotions for two weeks, leading to increased demand for deliveries. The union’s postal executive will meet on Thursday to discuss fresh action in the run-up to Christmas. It also plans to hold a vote among members on the deal Royal Mail announced on Monday, as well as a vote of no confidence in the chief executive, Simon Thompson. Royal Mail’s latest offer includes a 7% salary increase over two years, along with a lump sum payment worth 2% of pay this year. Its “conditional pay-for-change offer” was an attempt to end a long-running dispute over pay and conditions but the CWU called it a “derisory” offer that disguised a real-terms pay cut. The union said the widespread changes over introducing “Uber-style owner-drivers”, mail centre closures and changes to Sunday working had prompted widespread outrage from workers. The CWU general secretary, Dave Ward, said: “Posties are in the fight of their lives against the Uberisation of Royal Mail and the destruction of their conditions. “But 115,000 of our members will not just accept this war on their livelihoods and their industry. They will never give up the fight to protect this industry and to protect their hard-won working conditions. “Simon Thompson has to either accept that or walk away – until he does one or the other, serious disruption will continue.”