That contrasted with a 9.4 percent drop in department store sales in the following week ended Dec. 31, when there were fewer trading days due to the timing of public holidays.

The employee-owned firm reported similar trends at its upmarket grocery chain Waitrose, with sales in the week to Dec. 24, up 31.1 percent, on strong demand for sparkling wine and party food, while they fell 12.5 percent in the week to Dec. 31.

(Reporting by Sarah Young, editing by Paul Sandle)