LONDON (Reuters) - British supermarkets are frantically trying to build up their online operations during the coronavirus emergency but no matter how hard they work they will not have enough capacity to meet unprecedented levels of demand.

FILE PHOTO: Ocado delivery vans return to a depot in Hatfield as the spread of the coronavirus disease (COVID-19) continues, Hatfield, Britain, March 28, 2020. REUTERS/Paul Childs/File Photo

That has prompted the industry to call on Britons able to safely visit a supermarket to do so, leaving precious online delivery slots for the elderly and vulnerable.

With Britain in lockdown, analysts estimate about 25% of food purchasing has switched from cafes, restaurants and bars to the grocery retail sector as people adapt to the new way of living.

Prior to the health crisis about 8% of British grocery demand was ordered online, with 92% bought in stores. But major supermarkets are reporting demand has surged to about 75% of people wanting an online delivery.

Last week online supermarket pioneer Ocado said it had around 10 times more demand for its services than it did before the outbreak began. It has stopped registrations from new customers.

A source at another major supermarket group said its website offers delivery slots for three weeks out.

“The new slots go on every day at midnight, they go like Glastonbury tickets,” the source said.

“Even if we were all very creative, and despite all the pressures, doubled our capacity it still doesn’t touch the sides of what people would want.”

SLOTS

Dave Lewis, head of industry leader Tesco, last week asked customers who are able to safely come to stores to do so, instead of shopping online, so that it could start to free up more slots for the vulnerable.

Walmart owned Asda, the No. 3 player, is similarly requesting customers to shop in stores if possible so that delivery slots can be kept for those most in need.

Sainsbury’s, the No. 2, has given the elderly and vulnerable priority over all slots. Its customer “Careline” has been inundated, with the same number of people who use the service in an average year using it in just two weeks.

The problem for the industry, which could have repercussions for when the pandemic is over, is frustrating hundreds of thousands of regular online customers who miss out on slots during the crisis.

The government has provided Britain’s big supermarket groups with a list of 1.4 million highly vulnerable citizens and they are dividing them up between them on a pro-rata basis according to market share.

Inevitably this will mean they will have to “bin-off” some previously loyal customers.

Some commentators argue the government needs to take a more central role in how supermarkets provide food.

“Government has to get a grip and set new food cultural rules for how consumers are to behave. Previous governments in crises, in wars, have done this,” said Tim Lang, professor of food policy at City University London.

“This government is refusing to listen to the expert advice which has been given to them. This is unacceptable and setting up the retailers to fail.”