Supermarkets are restricting purchases across a wide range of products as they step up their efforts to combat panic buying.
Tesco and Sainsbury's are telling customers they can only buy three of any grocery item while they are also shutting fresh food counters.
Asda is taking similar action and Morrisons is limiting purchases across 1,250 lines.
The latest limits, which effectively ration purchases of a huge range of goods, significantly widen the scope of restrictions that had previously been implemented on a small number of items such as hand sanitiser.
Sainsbury's chief executive Mike Coupe said: "We have enough food coming into the system, but are limiting sales so that it stays on shelves for longer and can be bought by a larger numbers of customers."
A cap of two is being imposed on the most popular items, such as toilet roll, soap and long-life milk.
Meat, fish and pizza counters and cafes are being closed from Thursday to free up lorry and warehouse capacity, as well as shelf-stacking time, for essential items to be replenished.
Sainsbury's has also announced that its stores will only be open to customers over 70 and those with a disability for the first hour of trading on Thursday.
Plans are in place to beef up its "click and collect" offering, and these two groups will be given priority access when new slots become available.
Tesco, Britain's biggest supermarket, has suspended all-night opening in big stores so that shelves stripped bare by worried shoppers can be re-stocked.
It said vulnerable and elderly customers would be given priority between 9am and 10am on Mondays, Wednesdays and Fridays.
THe company's statement added: "Tesco store colleagues can't work from home and a good number of them will need to respond to personal or family challenges connected with dealing with COVID-19.
"So we would please ask that you understand the challenging environment in which we are all working. If you do go in-store and want to say thank you, then I'm sure they'd appreciate it."
Waitrose has drafted in 1,200 staff from sister retailer John Lewis to cope with demand.
The supermarket emailed customers on Wednesday to say that it too was "reluctantly" introducing limits on some of its most in-demand online items.
Morrisons reported that it had seen a "considerable" degree of stockpiling and its chief executive David Potts urged customers to "just buy what you need".
Asda is restricting shoppers to three items on all food and closing its cafes and pizza counters, while temporarily reducing the opening hours of all its 24-hour stores for re-stocking.
Discount rival Aldi said on Monday that it was limiting customers to four items of any one product.
Business secretary Alok Sharma said supermarkets were taking "sensible measures" and that he was confident in the "resilience" of the sector.
He told Sky News he understood the "rationale" of people wanting to stock up but said most consumers would be "extremely sensible".
Mr Sharma added: "As shelves get restocked I'm quite sure people will take the logical steps and actually shop as they would normally shop when they go to do their weekly or daily shop."
Supermarkets have seen a huge surge in demand for delivery services, with no slots available until next month in some areas.
Morrisons said on Monday that it planned to hire 3,500 more workers as it expands online delivery services to help it meet demand during the coronavirus crisis.
Supermarkets should get a boost from a business rates holiday announced by chancellor Rishi Sunak among a package of measures to deal with the economic fall-out of the COVID-19 crisis.
Sainsbury's welcomed the measures. It said it paid £500m in business rates on its stores in the financial year to March 2019.