British parcel delivery company City Link has gone into administration and temporarily suspended all operations, with 2,727 jobs at risk, administrators said on Thursday.
Hunter Kelly, an administrator from Ernst & Young, said undelivered parcels could be picked up at its depots from Monday and "substantial redundancies" were expected.
"This is the bitterest blow any group of workers could receive on Christmas Day," said Mike Cash, general secretary of the RMT trade union.
"It is absolutely shocking that the company have sprung this announcement once all the Christmas deliveries have been completed," he said.
Kelly said in a statement that the company had been hit by intense competition, changing market needs and difficulties in cost-cutting.
"Despite the best efforts to save City Link Limited, including marketing the company for sale, it could not continue to operate as a going concern," Kelly said.
The company's website said it began delivering parcels in 1969 and had an annual turnover of £300 million (382 million euros, $467 million).
But Kelly said it had suffered "substantial losses over several years" and had "all but used up" a £40-million investment made in 2013.