All Carphone Warehouse stores will be shuttered on 3 April in what parent company Dixons Carphone has called "an essential step" in its turnaround plans.
The Carphone Warehouse brand will continue to operate inside larger Currys PC World stores.
Dixons Carphone said that nearly 40 per cent of affected employees will remain with the business in different capacities, but around 2,900 will be made redundant.
CEO Alex Baldock said the decision has been driven by changing customer buying habits, particularly as customers now want to buy all their tech in one place.
"Customers are changing how they buy technology, and Dixons Carphone must change with them," he said. "We're underway with a fundamental transformation to do so.
"Today's tough decision is an essential part of that, the next step in making our UK mobile business a success for customers, colleagues and other shareholders.
"Clearly, with unsustainable losses of £90m expected this year, mobile is currently holding back the whole business. There is never an easy time for an announcement like this, but the turbulent times ahead only underline the importance of acting now."
Dixons Carphone said the stores that it is closing represent around eight per cent of its selling space in the UK.
The 70 stores in the Republic of Ireland will not be affected, it added.
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Around 2,900 jobs to be cut