Phones 4U, the high street mobile phone retailer, is closing its 550 standalone stores after operators Vodafone and EE cut ties with the business.
The stores will remain closed until administrators at PwC decide on whether the business can reopen for trading.
The firm said it had a healthy balance sheet with profits of more than £100m but had no option but to go into administration.
A note on its website says: “Dear customer, following the unexpected decision of EE and Vodafone to withdraw supply from Phones4U, we regret that we are offline.
“Please accept our apologies and we will update you as soon as possible. Thank you for your custom, the heartbroken Phones4u Team.”
Phones 4U was set up by John Caudwell in the 1980s. He sold it for £1.5bn in 2006.
samantha.mcclary@estatesgazette.com