Retail chain John Lewis Partnership saw an 11% rise in sales in the last week of 2018 compared with a year earlier.
The partnership includes both John Lewis department stores and Waitrose supermarkets.
Waitrose sales provided most of the year-end boost, rising 19.2% on the same week a year ago.
John Lewis reported very strong sales on Christmas Eve itself – which was included in the last week of trading – as customers bought last-minute gifts.
Gift food sales at John Lewis doubled, while beauty and well-being products saw a 25% increase.
However, in the previous week, ending on 22 December, sales across the partnership fell 4.8%. Its financial year so far has seen sales remain flat in both Waitrose and John Lewis.
A Waitrose spokesperson said: “As always at this time of year, our sales figures are heavily distorted by the fall of Christmas and New Year. Both these weekly performances were in line with expectations.”