Market researcher Kantar said Aldi's sales increased 18.7% over the 12 weeks to Sept. 4, taking its UK grocery market share to 9.3% from 8.1% a year ago. Morrisons' sales fell 4.1%, with its share falling to 9.1% from 9.8%.

Aldi trails market leader Tesco, Sainsbury's and Asda. Aldi and fellow discounter Lidl account for 16.4% of the market.

Morrisons had been No. 4 since it took over Safeway in 2004. It has been owned by U.S. private equity firm Clayton, Dubilier & Rice (CD&R) since October.

"Back at the start of the 2010s, Tesco, Sainsbury's, Asda and Morrisons together accounted for over three quarters of the sector but that traditional big four is no more," said Fraser McKevitt, Kantar's head of retail and consumer insight.

The researcher said grocery inflation hit 12.4% in the four weeks to Sept. 4, another record, adding 571 pounds ($670) to the average annual grocery bill.

It said products like milk, butter and dog food are jumping up especially quickly at 31%, 25% and 29% respectively.

Kantar said total grocery sales by value rose 3.8% in the 12 week period, with sales of the very cheapest own label products up by a third compared with a year ago.

UK grocers' market share and sales growth (%)

Market share Market share % change in

12 wks to 12 wks to sales

Sept. 4 2022 Sept. 5 2021 (yr-on-yr)

Tesco 26.9 27.4 1.9

Sainsbury's 14.6 15.0 1.5

Asda 14.1 14.4 2.2

Aldi 9.3 8.1 18.7

Morrisons 9.1 9.8 -4.1

Lidl 7.1 6.1 20.9

Co-operative 6.5 6.5 2.7

Waitrose 4.7 5.1 -4.7

Iceland 2.4 2.3 5.8

Ocado 1.7 1.7 5.2

Source: Kantar

($1 = 0.8541 pound)

(Reporting by James Davey; Editing by Hugh Lawson)

By James Davey