Energy giant Npower is to close most of its eight UK sites threatening thousands of jobs.
Unions have described the move as a "body blow", coming just weeks before Christmas.
The company, which has 5,700 staff, is in "a critical and unsustainable business situation", according to its owner innogy, which is part of German-based E.ON.
Under the shake-up Npower's domestic and small business customers will be dealt with by E.ON UK customer services.
Innogy said this would "create substantial synergies from running a single customer service platform rather than two".
It added: "The remaining Npower operations would be restructured over the next two years.
"This would include the closure of the majority of Npower's sites and corresponding staff reduction."
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Npower has eight sites at Oldbury in Gloucestershire, Hull, Leeds, Birmingham, Solihull, Sunderland, Swindon and Worcester.
No indication has been given which of these will be spared by the cull.
Leonhard Birnbaum, chief executive of innogy SE said: "The question of how to improve the performance of our retail business in the UK, Npower, has been a key issue for the past few years.
"I want to express my sincere thanks to our employees for their unceasing dedication to delivering a great service to our UK customers in a very challenging market.
"We know that this is bitter and surprising news for many of our Npower employees and we are well aware of our responsibility towards our employees in the months ahead."
He added: "What became clear to the Npower Board and ourselves is that Npower with its structural set-up and scale was not able to succeed by itself in this difficult market.
"Together with E.ON, we now propose to reduce the cost of serving Npower customers by combining them onto one platform, an option that simply was not available in the past."
Johannes Teyssen, chief executive of E.ON said: "The UK market is currentlRead More – Source