Unite is objecting to Royal Mail plans to “cut 700 jobs and slash pay by up to £7,000”.
The union said it was given no other option than to endorse a “ruinous” course as the business is “awash with cash”.
Unite claimed Royal Mail reported £311 million in profit and paid out £400 million to shareholders while proposing cuts for workers “so savage they will destroy the service”.
Sharon Graham, the union’s general secretary, said Royal Mail chiefs were driving a 500-year-old “essential” service “close to ruin”.
She said: “This business is awash with cash but it is putting profits and dividends for the few at the top ahead of its duties as a public service.
“There is not a single aspect of these cuts which is about improving customer service.
“They are being driven entirely by a culture of greed and profiteering which has seized a 500-year-old essential service, driving it close to ruin.
“Our members are determined to force the business to take a different path, and they have the full backing of Unite.”
