Consumers have been preparing to taste the difference this Christmas as they stock up on supermarkets' premium own label brands.
Data from Kantar Worldpanel showed that during the three months to the end of 4 December, shoppers spent 13 per cent more on brands such as Tesco Finest and Asda Extra Special than they did the year before.
However, overall supermarket sales grew by just 0.7 per cent.
Kantar said that both Morrisons' The Best and Asda's Extra Special lines were selling particularly well, with sales up by 35 per cent and 15 per cent respectively.
Fraser McKevitt, head of retail and consumer insight at Kantar Worldpanel, said: "Over Christmas it's likely that premium lines will record their highest ever sales figures as even more shoppers trade up to treat their loved ones.
"Top-tier private label finds its way into 12 per cent of shopping trips, with 88 per cent of consumers now buying from these lines.
"In the past 12 weeks, 6.3 per cent of own label purchases were from premium lines such as Tesco Finest and Sainsbury's Taste the Difference, well ahead of the 5.7 per cent recorded last year."
Despite the fall in the value of the pound following the Brexit vote, inflation has still not fed through into Britons' shopping baskets. Kantar said a typical grocery basket was 0.1 per cent cheaper than it was at the same time last year.
There have been price rises in particular food categories, however. Fresh fish was up 5.3 per cent annually, and chilled ready meals were up 2.3 per cent.