The UK grocery market has returned to marginal growth as sales picked up driven by pre-Christmas price discounts, according to the latest grocery share figures from Kantar Worldpanel.

Grocery sales for the 12 weeks to 7 December rose by 0.1%, having fallen by 0.2% over the three months to November.

Each of the big four supermarkets saw year-on-year sales and market share declines, with Asda slipping further into negative and losing market share for the first time this year.

Morrisons saw the biggest sales fall, dropping 3.2% and seeing its market share contract to 11.6% from 11.2% year-on-year.

Tesco’s sales were down 2.7% and market share was 29.1% (29.9% last year), marking its best performance since June. Sainsbury’s saw a 1.8% sales fall and a 0.3 percentage point market share decline to 16.5%, while Asda’s market share slipped 0.2 percentage points to 16.7% after a 1% sales decline.

Fraser McKevitt, head of retail and consumer insight at Kantar Worldpanel, commented: “Britain’s supermarket price war is ramping up ahead of the all-important Christmas period. Retailers are selling more items on promotion, leading to like-for-like prices falling by 0.7% compared with this time last year.  Cheaper groceries are an early Christmas present for shoppers, saving them £182 million in the past 12 weeks alone but this puts pressure on the supermarkets.”

Waitrose bucked the declining trend, with its sales rising 6% to increase its market share to 5% (from 4.7% last year).

That just keeps Waitrose ahead of Aldi, which grew its market share from 4% to 4.9% after a sales boost of 22.3%. Lidl grew by 18.3% to take its market share to 3.7% (3.1% last year) and grow the combined share of the discounters to 8.6%.

Sales declines were also seen at The Co-op (-1.6%), Iceland (-1.6%) and Farmfoods (-7.3%).