Tesco shares rose to the top of the FTSE 100 this week, jumping 1.5 per cent to 215p - but the results come amid a difficult time for the retail sector, as consumer confidence takes a knock from Brexit worries.

Chief executive David Lewis said that “sensible” Brexit contingency planning is under way and Tesco is working with suppliers to stockpile goods.

He said the supermarket has been holding a special round of talks with its suppliers and increasing stocks of long-life groceries.

But, with Britain importing about half the fresh food it eats, Lewis said it was not possible to make similar arrangements for fresh food if Britain crashes out of the EU.

“It’s hard to contingency for fresh food, where we can’t stockpile.

“Like other retailers, we’d be keen that there is no friction at the border given the UK imports half of the fresh food it eats,” he said.

Supermarkets are also battling rising costs and fierce competition in the sector as Lidl and Aldi continue their relentless march.

As part of efforts to position the supermarket to meet the challenges of a rapidly changing market, Mr Lewis has forked out £3.7 billion to acquire cash-and-carry business Booker and launched Jack’s, a discount chain that will supposedly rival the German discounters.

Meanwhile, Marks & Spencer said its own Brexit planning committee had “upped the ante” and started to make a “few real choices”.

Chief executive Steve Rowe, said: “We have taken some additional long-life stuff but our food business is 70 per cent fresh and anything that slows down will contribute to cost and waste.”