The umbrella organisation behind the combined T-Mobile and Orange brands is to cut 1,200 jobs in the UK from its 16,000-strong workforce.
Everything Everywhere said the cuts will affect areas including back office, headquarters and management as part of a restructuring plan that was expected when the two operators merged.
Tom Alexander, chief executive of Everything Everywhere, said in a statement that he "regretted" some roles had to go, but is confident the move is the best decision for the company.
"We need to ensure we are operating with maximum efficiency, effectively serving two brands while removing any unnecessary duplication from the business, " he said.
"With the size and scale of our combined business, we have an incredible opportunity to deliver an unrivalled experience and unparalleled value to our customers."
The company claimed that no frontline customer service or retail staff will lose their jobs, and that both consumer brands will retain dedicated marketing teams.
The cuts follow an announcement that Everything Everywhere will expand its retail footprint and increase its network from 16,000 radio sites to 18,000.
Customers on both networks will be able to access either network from 5 October as part of an overall commitment to develop and combine 3G, 4G, fixed broadband and Wi-Fi networks in future, according to Everything Everywhere.
The company recently announced a 4.8 per cent fall in revenue for the second quarter of 2010 compared with the same period in 2009, from £1.8bn to £1.72bn.
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