Tesco has achieved its highest market share since December 2017, while overall supermarket sales are expected to exceed £13bn over the festive period for the first time ever, new data shows.

According to Kantar, Tesco now holds 28.1% market share as its sales jumped 5.2% in the 12 weeks to 1 December.

Sainsbury’s market share also increased by 0.3 percentage points to 15.9% as spending through its tills rose 4.7% year-on-year.

Tesco and Sainsbury’s now have a combined market share of 44%.

Meanwhile, online supermarket Ocado boosted sales by 8.7% over the period with a 1.8% share of the market. It outpaced the total online market, which grew by 3.6%, with shoppers spending £4.2bn on the channel overall across the 12 weeks.

Lidl was named the fastest growing bricks-and-mortar grocer, with sales up 6.6% while its market share share climbed 0.3 percentage points to 7.7%. Footfall at the discounter also ramped up nearly 10% year-on-year.

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Spending at Morrisons, which now takes 8.6% of the market, rose by 2%, while Waitrose grew slightly ahead of the market with increased spending of 2.6%.

Spending at Aldi grew by 2.1% during the period.

Kantar head of retail and consumer insight Fraser McKevitt said: “The number of different retailers we visit in the run up to Christmas is higher than at other times during the year, including wider high street brands like M&S.

“Just under one in three households, at 32%, bought food, drink and other groceries to have at home from M&S during the 12 weeks to 1 December and looking at grocery sales alone, spending at M&S rose by 10.4%.”

It comes as take-home sales at the grocers increased by 2.5% over the four weeks to 1 December and supermarket sales are expected to continue growing, exceeding £13bn over the period for the first time ever.

McKevitt said: “Monday 23^rd December is likely to be the single busiest day for the supermarkets this year, although there are clear signs that shoppers are already stocking up their cupboards.

“Sales of assorted sweet biscuits and biscuits for cheese both doubled in November compared with the month before, while 8% of us bought a Christmas pudding.”

The proportion of spending on premium own-label products is also set to climb to nearly 7% in December as Kantar said it had already reached 5% over the latest four weeks.