Phones 4u has confirmed that it will enter into administration with PwC.
The news comes after one of its last remaining mobile operations partners EE cut ties with the retailer on Friday (September 12).
The company indicated in a press release today (September 14) that 550 Phones 4u standalone stores will close until a decision about its future is made by the new administrator.
More than 5,000 staff members will be briefed by management, although Phones 4u's private equity owner BC Partners has said that it is "intended that employees will continue to be paid until further notice".
Ongoing mobile contracts taken with the retailer will not be interrupted.
EE accounted for around half of the retailer's £1b sales, but cut ties after a strategic review, just as Vodafone and O2 had done earlier in the year.
Phones 4u chief executive David Kassler said in a statement: "Today is a very sad day for our customers and our staff. If the mobile network operators decline to supply us, we do not have a business.
"A good company making profits of over £100 million, employing thousands of decent people has been forced into administration.
"The great service we have provided should have guaranteed a strong future, but unfortunately our network partners have decided otherwise. The ultimate result will be less competition, less choice and higher prices for mobile customers in UK."
BC Partners spokesperson Stefano Quadrio Curzio added: "Our overriding concern is for all the dedicated hard-working employees of Phones 4u at a time of uncertainty for the company.
"Vodafone has acted in exactly the opposite way to what they had consistently indicated to the management of Phones 4u over more than six months. Their behaviour appears to have been designed to inflict the maximum damage to their partner of 15 years, giving Phones 4u no time to develop commercial alternatives.
"EE's decision on Friday is surprising in the context of a contract that has more than a year to run and leaves the board with no alternative but to seek the administrator's protection in the interests of all its stakeholders."
The news comes after one of its last remaining mobile operations partners EE cut ties with the retailer on Friday (September 12).
The company indicated in a press release today (September 14) that 550 Phones 4u standalone stores will close until a decision about its future is made by the new administrator.
More than 5,000 staff members will be briefed by management, although Phones 4u's private equity owner BC Partners has said that it is "intended that employees will continue to be paid until further notice".
Ongoing mobile contracts taken with the retailer will not be interrupted.
EE accounted for around half of the retailer's £1b sales, but cut ties after a strategic review, just as Vodafone and O2 had done earlier in the year.
Phones 4u chief executive David Kassler said in a statement: "Today is a very sad day for our customers and our staff. If the mobile network operators decline to supply us, we do not have a business.
"A good company making profits of over £100 million, employing thousands of decent people has been forced into administration.
"The great service we have provided should have guaranteed a strong future, but unfortunately our network partners have decided otherwise. The ultimate result will be less competition, less choice and higher prices for mobile customers in UK."
BC Partners spokesperson Stefano Quadrio Curzio added: "Our overriding concern is for all the dedicated hard-working employees of Phones 4u at a time of uncertainty for the company.
"Vodafone has acted in exactly the opposite way to what they had consistently indicated to the management of Phones 4u over more than six months. Their behaviour appears to have been designed to inflict the maximum damage to their partner of 15 years, giving Phones 4u no time to develop commercial alternatives.
"EE's decision on Friday is surprising in the context of a contract that has more than a year to run and leaves the board with no alternative but to seek the administrator's protection in the interests of all its stakeholders."