Grocery sales in March were the highest ever recorded - up 20.6 per cent on the previous year.

The latest grocery market share figures from Kantar show year-on-year supermarket sales grew by the fastest rate in over a decade - up 7.6 per cent over the last 12 weeks as a whole.

Fraser McKevitt, head of retail and consumer insight at Kantar, said: "It has been an extraordinary month and social distancing measures have had a profound impact on all our daily lives - from the way we work and socialise, to how we shop and care for our loved ones. Retailers and their staff have been on the frontline as households prepare for an extended stay at home, with grocery sales amounting to £10.8 billion during the past four weeks alone - that's even higher than levels seen at Christmas."

While week-on-week sales were growing strongly at the beginning of the month, it was on Monday 16 March that the public headed to the shops in unusually high numbers. Between Monday 16 and Thursday 19 March, 88 per cent of households visited a grocer, making five trips on average - adding up to 42 million extra shopping trips across four days.

Growth has been primarily driven by people making additional shopping trips and buying slightly more, rather than a widespread increase in very large trolleys. The average household spent an extra £62.92 during the past four weeks, equivalent to adding five days' worth of groceries.

Fraser McKevitt said: "It's inevitable that shoppers will add extra items to their baskets when faced with restrictions on their movement and possible isolation if one of them becomes unwell, but many families are also adjusting to having more mouths to feed. Those with children over the age of 16 spent £508 this month on average, £88.13 more than they did in March 2019 - a trend that likely reflects students returning home from college and university.

"With restaurants and cafés now closed, none of us can eat meals on the go any longer and an extra 503 million meals, mainly lunches and snacks, will be prepared and eaten at home every week for the foreseeable future.

"Government advice may have been to get groceries delivered if possible, but limited delivery slots meant that only 14.6 per cent of households received an online delivery in the past four weeks, up from 13.8 per cent in March 2019, but probably well below actual demand."

During this time of unprecedented demand, all 10 of the largest retailers were simultaneously in growth for the first time since October 2018. Independent retailers and symbol group stores, including Londis, Spar, Nisa, Premier and Costcutter, provided access to groceries close to home, and sales rose collectively by 16.1 per cent.

Sales at Lidl were up 17.6 per cent during the 12 weeks, as its market share increased by 0.5 percentage points to 6.1 per cent, while Aldi reached a new record high market share of 8.2 per cent, growing sales by 11 per cent.

Sainsbury's was the fastest growing of the big four, with sales up by 7.4 per cent, followed by Tesco at 5.5 per cent, Asda at 4.9 per cent and Morrisons at 4.6 per cent. Iceland benefited from shoppers stocking up on frozen items, with a sales increase of 11.7 per cent .