According to Reuters, on traditionally one of the busiest shopping days of the year, large queues snaked around some Tesco, Sainsbury's, Waitrose, Marks & Spencer, Aldi and Lidl stores, according to Reuters reporters across London.

Many shoppers were buying traditional Christmas fare, or adapting it after Prime Minister Boris Johnson imposed stricter measures from Sunday which have stopped many families meeting up and pushed people to rush to buy food for their own gatherings.

"Sunday was exceptionally busy - today has gone bananas," said one supermarket manager.

At Waitrose in Clapham, many shoppers had planned to leave London to see family for the festive period but were now stocking up for a Christmas in the capital.

Meat and milk were sold out in some supermarkets but traditional panic buying targets such as baked beans and pasta were in good supply.

Gaps will start to appear on British supermarket shelves within days if transport ties with mainland Europe are not quickly restored, Sainsbury's warned on Monday.

Sainsbury's said all products for "the Great British Christmas lunch" were already in the country and it had plentiful supplies of these.

Johnson's spokesman said supply chains were resilient.

"It remains the position that people should shop normally," the spokesman said.