Discount supermarkets Aldi and Lidl have seen their joint share of the groceries market double to 10% in just three years, industry figures show.
Analysts Kantar Worldpanel said Aldi, which has a Newton Aycliffe store, enjoyed a 5.6% market share in the 12 weeks to November 8 this year.
Lidl has seen its national market share climb to 4.4%.
Sainsbury’s was the only one of the “big four” supermarket chains to increase sales and market share.
As a result, Kantar said Sainsbury’s had overtaken Asda to become the second-largest UK supermarket chain, after Asda saw like-for-like sales fall 4.5% in the three months to the end of September, its fifth quarter of falling revenue.
In the previous quarter, Asda’s sales slumped 4.7%, marking its worst performance in its 50-year history.
It said sales volumes remained under pressure from discount supermarkets.
Meanwhile its US parent Walmart said net profit had fallen to $3.3bn for the three months to the end of October from $3.7bn a year earlier.
Its total revenues fell 1.3% in its third quarter to $117bn compared with $119bn a year earlier.
Asda is now the worst performing of the four main supermarkets.
Tesco remains the UK’s largest supermarket with a 27.9% market share, while Sainsbury’s has 16.6%, with Asda on 16.4%.
UK supermarkets’ share of grocery market
Tesco 27.9%
Sainsbury’s 16.6%
Asda 16.4%
Morrisons 10.8%
The Co-operative 6.3%
Aldi 5.6%
Waitrose 5.2%
Lidl 4.4%
Source: Kantar Worldpanel (12 weeks to November 8, 2015)