Energy giant Npower has announced plans to restructure its UK business, leading to the loss of up to 4,500 jobs and the closure of a number of call centres.

The news was described as a "body blow" by unions, especially coming just weeks before Christmas.

Workers were given details at briefings on Friday, with the company saying it was facing an "unsustainable business situation" which has persisted for a number of years.

The job losses will take place over the next two years, mainly at call centres. Npower has eight call centres south of the Border.

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Johannes Teyssen, chief executive of Npower's owner, E.ON, said: "The UK market is currently particularly challenging.

"We've emphasised repeatedly that we'll take all necessary action to return our business there to consistent profitability.

"For this purpose, we've put together proposals and already begun discussing them with British unions."

E.ON UK chief executive Michael Lewis said: "With Npower becoming part of the new E.ON - creating the second largest supplier in the UK - we need to build a sustainable business with a lower cost base that allows us to compete in this extremely challenging market.

"We are proposing a number of steps to create an E.ON business that can be both sustainable and successful for the future whilst also fully supporting and serving our customers today."

A GMB spokesman said: "Clearly this announcement will be a body blow to Npower workers across the UK.

"The Government has to urgently wake up to the impact that the price cap is having on good and reasonably well-paid jobs in UK energy companies."

Customers at HSBC and Santander are to share a multimillion-pound windfall after the two banks were ordered to pay back overdraft fees.

The Competition and Markets Authority (CMA) said HSBC had failed to text 115,000 customers when they went into an unarranged overdraft, and would have to refund them £8 million.

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Meanwhile, Santander also broke the rules in six different ways, more than HSBC's two breaches.

It has agreed to pay back the customers that it did not text; however, it has yet to work out how many there are, or how much it owes them.

Customers will get back all the fees they racked up on their overdrafts, if they were not warned when going into the red.

The CMA said in a statement: "The refunds paid by the banks cover all fees incurred by customers from going into unarranged overdrafts where they had not been warned beforehand by the required text alerts."

Ocado will hire almost 400 developers in the UK after it signed a multimillion-pound deal to provide its online shopping platform to one of Japan's largest retailers.

Finance director Duncan Tatton-Brown said management was looking for 400 people to work at its development centres.

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Most of these will be in the UK, split between its sites in London's Old Street and in Hatfield.

There will also be more head office roles in the UK and more jobs created in the places it operates.

"These jobs are outside of the other roles that we are creating, both head office roles here in the UK, but also some roles in the territories where we operate," Mr Tatton-Brown said.

Ocado will open its first warehouse in the region around Tokyo for Japan's Aeon in 2023, it said on Friday.

The Japanese supermarket has around 100 million customers and employs 580,000 staff. It will use Ocado's software to bring them online shopping and delivery.

Ocado did not say how much the deal is worth but its operating costs are set to rise by £25 million in 2020 as a result.

The first of the warehouses will be built in the Kanto region, which includes Tokyo.