A bitter war of words has erupted between a workers' union and the owners of a U.K. delivery company that notified its workers of impending redundancies in an email on Christmas Day.

More than 2,000 staff at City Link will be let go on New Year's Eve, as the company goes into administration due to a "continued lack of profitability." Investment firm Better Capital, which owns City Link, said it regretted the decision, but defended the timing of the announcement.