Marks & Spencer is said to be luring customers away from supermarket rivals after a shift towards early Christmas shopping.
According to data seen by the Mail on Sunday, the grocer has seized market share from every major competitor except Lidl and Ocado.
It suggests the retailer’s festive peak, when shoppers “trade up” for better quality food, has moved forward this year.
After warnings of Christmas food shortages and supply chain mishaps, people are thought to be starting their shopping early.
Kantar analysts recently claimed that sales of frozen turkey are twice as high as normal.
Iceland boss Richard Walker said turkey sales were up 400 per cent, but added that the retailer was not seeing “crazed panic-buying”.
Marks & Spencer had suggested it was on the road to recovery in August, when its trading update showed food revenue had leapt 10.8 per cent.
Most other supermarkets saw their growth slump into the decimals.
However, this could reflect Marks & Spencer’s low base, with food sales inching up 1.3 per cent last year as others saw double-digit increases.