Up to 2,500 Royal Mail employees could lose their jobs under an 'organisational review', the company has announced.
The expected job losses will come at Royal Mail's head office in Farringdon Road, London, and within support function roles by the end of 2027.
Around 131,000 people are employed by the firm in total.
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A statement said of the proposed job losses: "This is subject to consultation and we anticipate the changes would be achieved through natural attrition and a voluntary redundancy programme, with no compulsory redundancies.
"There would be no reductions in operational frontline roles in delivery and processing, including posties and drivers."
The company said it was undergoing a "significant transformation" as the business implements universal service reform and adapts to a rapidly-changing market that has seen letter volumes decline sharply and parcel demand surge.
Its chief executive, Alistair Cochrane, said: "We have been working hard to reduce costs and simplify processes across all areas of the business as we transform to win in a very competitive market.
"These proposed changes remove duplication and allow us to invest further in the service we deliver for our customers.
"We are committed to treating everyone fairly and respectfully throughout this process, working closely with our trade unions.
"The proposed changes will not be easy, but they are an important part of building a stronger, simpler and future-ready Royal Mail for our customers and colleagues."
The job cuts represent the first main organisational shift under the ownership of Czech billionaire Daniel Kretinsky's EP Group.
It paid almost £3.6bn for Royal Mail's parent firm last year - overcoming both government and union concerns in return for a series of pledges, including to the company's universal service obligation.
However the commitments covering deliveries six days a week were later allowed, by the industry regulator, to be relaxed for second-class letters.
Despite the change in ownership, union relations with Royal Mail's management continue to be strained following a series of bitter disputes and strikes under the old regime.
The Communication Workers Union (CWU) has long accused the company of managed decline in a market that, it says, has been allowed by Ofcom to undercut its 100,000 Royal Mail members' terms and conditions.
The union, along with Unite which also represents staff affected by the planned cuts, were yet to comment.
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