Comet is to close a further 125 stores – with the loss of 2,500 jobs – over the next few weeks, and it may shut down its entire business before the end of the year unless a buyer can be found, the administrator, Deloitte, has warned.

More than 1,000 jobs have been cut so far across the 41 stores already shut, and all 5,000 remaining staff are at risk of being unemployed by Christmas.

The 70 stores that remain open will continue trading until all their stock has been sold and, with a last-minute takeover looking unlikely, it would be the biggest retailing collapse since Woolworths, which went into administration four years ago this week, with the loss of 24,000 jobs.

Comet's joint administrator, Chris Farrington, said: "We remain in discussions with a small number of interested parties and hope that a positive outcome can still be achieved. Should any acceptable offers be received for stores we will delay the closure process. Unfortunately, in the absence of a firm offer for the whole of the business, it has become necessary to begin making plans in case a sale is not concluded. If a sale is not possible we would envisage stores to begin closing in December."

Deloitte is also proposing to shut the company's distribution centre in Harlow on Friday and will cut office functions at Rickmansworth in Hertfordshire, Hull and Clevedon, near Bristol.Rivals including Dixons Retail and TK Maxx are thought to be in talks to buy some Comet stores, while Appliances Online wants to buy the Comet brand and website to launch an online-only retailer.

The entrepreneur Clive Coombes is reportedly meeting with administrators today, however, funding for a possible offer to buy 180 is unclear.

If a buyer cannot be found around 6,100 workers will be left unemployed in the latest High Street retailing collapse which has seen Clinton Cards, JJB Sports, La Senza, Game, Oddbins and Barratts collapse.