Tesco’s sales outpaced its big four rivals in January but the rapidly growing discounters continued to erode its market share.

Britain’s biggest retailer grew revenues 2.6% in the 12 weeks to January 28, according to data from Kantar Worldpanel.

However, its market share dipped 0.3 percentage points to 27.8% as Aldi and Lidl further eroded the big four’s market share.

Lidl was the fastest-growing grocer during the period, registering a 16.3% spike in sales.

The increase narrowly outpaced its fierce rival Aldi, which enjoyed a 16.2% jump.

Among the big four, Morrisons and Asda both recorded 2.2% revenue climbs, while Sainsbury’s was the worst-performing member of the leading supermarket players, with sales up 1.5%.

Etailer Ocado emerged as the fastest-growing grocer outside of the discounters, as sales advanced 7.8%. Waitrose and Iceland’s revenues rose 1.6% and 1.5% respectively.

The Co-op suffered a 0.1% slip as total revenues continued to be impacted by the sale of 298 stores to McColl’s.

According to Kantar’s data, shoppers spent £1.6bn less on groceries in January than they did during December, as consumers reined in their post-Christmas spending.

On average, shoppers spent £3.39 less every time they shopped in January and sales of the grocers’ premium own-label lines almost halved.

However, total grocery sales increased 3.4% across the 12 weeks, spurred by inflation of 3.6%.

Nielsen data

Rival data from Nielsen also anointed Tesco as the fastest-growing member of the big four during the same 12-week timeframe, suggesting that the supermarket giant registered a 3.4% sales increase.

Asda gained further momentum with a 2.5% increase, while sales at Morrisons and Sainsbury’s advanced 1.9% and 1.1% respectively.

Nielsen backed up Kantar data in establishing Lidl as the fastest-growing grocer, suggesting that the discounter’s revenues spiked 17.2% across the three-month period.

Aldi sales jumped 12.6%, while Marks & Spencer and Iceland both outpaced the big four with 3.7% increases.

Nielsen UK head of retailer insight Mike Watkins said consumers were “in an economising mood” during January and “may have cut back” on groceries following the festive season.