Category manager Andy Phelps told suppliers at a conference earlier this month that the supermarket plans to promote less than it ever has. According to suppliers present at the conference, Phelps said it wasn't possible to sustain high levels of alcohol promotions given the highly inflationary cost pressures the industry is facing.

"It's an interesting gamble because liquor has always been a footfall-driving category and incredibly promotionally driven, but you can't argue with the rationale. You can't rely on promotions to keep hitting volumes," one supplier said.

"It is clear that Sainsbury's is openly advocating the need and intention to sell more off promotion, which will be more sustainable for all," another supplier added.

Sainsbury's ran the second-highest number of wine promotions among the major five supermarkets in the past 12 months, according to Brandview.com. It has run 2,299 wine deals in the past year, compared with 2,576 from Tesco, 1,682 at Morrisons, 1,342 by Waitrose and 623 at Asda.

A Sainsbury's spokeswoman declined to comment as the retailer is in its close period.