The changes the UK's supermarkets are making as demand rises due to coronavirus outbreak
Tesco has become the latest grocer to limit the number of products customers can buy in stores, as it tries to cope with the huge demand from the Covid-19 outbreak.
The UK's biggest supermarket said shoppers will be limited to buying just three products per line from Thursday.
It comes as shoppers were pictured queuing outside Morrisons in Bramley before it opened on Thursday morning.
Tesco Chief executive Dave Lewis added all counter services will close, to free up staff to restock shelves, and a priority hour will be launched at larger stores between 9am and 10am every Monday, Wednesday and Friday.
Stores that previously opened 24 hours, will also now close at 10pm each evening.
Online grocer Ocado.com also announced it would be shutting down its entire website and app until Saturday, to allow for changes to ensure more delivery slots are available.
Anyone with an order due will still receive their delivery while the website is down, Ocado added.
The moves follows similar measures by Sainsbury's, Aldi, Asda and Morrisons, to ease stockpiling pressure amid the Covid-19 outbreak.
Sainsbury's revealed it will only allow customers to buy a maximum of three of any single item, while Morrisons said it is limiting purchases across 1,250 lines.
Asda also announced it 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.
Aldi has already introduced limits of four items per shopper across all products.
Tesco boss Mr Lewis wrote to staff on Wednesday: "It is fair to say that we find ourselves in uncharted waters. Covid-19 is bringing a change to the UK and it's clear that lots of things are going to have to shift around in order to help us cope.
"At Tesco, we have been doing everything we can to keep business as usual, but we now have to accept it is not business as usual.
"In the last two weeks, we have seen significant and prolonged increases in demand across all of our stores and this is leading to shortages in some products for some customers."
It comes as Britain's supermarket chains are also launching action to help elderly and vulnerable customers, while ramping up operations to meet surging demand for home deliveries.
Sainsbury's became the latest group to offer priority home delivery slots to elderly and vulnerable customers, as well as exclusive shopping hours.
Its supermarkets will only open to these two groups for the first hour of trading on Thursday, chief executive Mike Coupe said, but will open for an hour longer so other shoppers do not miss out. Sainsbury's Local convenience stores will not offer the service.
Supermarkets have seen a huge rise in demand for delivery services, with no slots available until next month for both Tesco and Waitrose in some parts of the south east.
The surge came as Transport Secretary Grant Shapps authorised a temporary relaxation, until April 16, of the drivers' hours rules to help deliver goods to stores across the country.
A Department for Transport statement said the relaxation applies only to drivers supplying food and "essential products to supermarkets".
The statement added: "This includes the movement of such goods from importers, manufactures and suppliers to distribution centres. It does not apply to drivers undertaking deliveries directly to consumers."
Iceland outlets across the country have also introduced reserved time slots to give the vulnerable and the elderly a chance to shop in store.
Sainsbury's said customers over 70 and those with a disability will have priority access to online delivery slots from Monday, and the chain is also expanding its "click and collect" service.
Mr Coupe added that as of Thursday, Sainsbury's will be closing its cafes and its meat, fish and pizza counters to free up freight capacity for essential products.
Customers will also only be able to buy a maximum of three of any grocery product and a maximum of two on the most popular items such as toilet roll, soap and UHT milk from Wednesday onwards.
Elsewhere, The Original Factory Shop said it will give exclusive access to older customers between 8.30am and 9.30am from Monday to Thursday at its 167 stores until further notice.