Grocery sales were robust in December, up 6.7% in the four weeks to December 26 against the same period last year.

According to Nielsen, sales in the last two weeks of the period were up 8% year-on-year.

Nielsen senior manager retailer services Mike Watkins said: “We had a slow start to the season and from the figures it looks like consumers held back until the final fortnight where we saw some exceptional growths.”

Nielsen said Waitrose was the star performer driven by new stores. The grocer was up 14% for the period.

Morrisons was up 11.8%, Asda was up 8.6%, Sainsbury’s up 7.7% and Tesco was up 7.4%. Also, it said the Co-op benefitted from its merger with Somerfield, up 11.4%.

The research company said promotional activity remained at 35%. Watkins said: “Shoppers shared in the bonanza – price cuts, bigger than ever promotions and loyalty scheme give-aways all helped encourage shoppers to spend.”