Supermarkets will be limiting the amount of people allowed in their shops to as few as 10, new guidelines showed on Thursday.
Blanket guidance from Public Health England for supermarkets on social distancing measures will be provided shortly.
Tesco has released detailed information for all its store managers, with 10 people allowed at a time in the chain's smaller shops, and 300 in its superstores.
A Waitrose source told The Telegraph that the company was testing capacity limits, with 25 people allowed in smaller stores and 75 in big supermarkets.
Security guards are being drafted in to Britain's food retailers, to enforce social distancing during the coronavirus epidemic and ensure a one in, one out policy in shops which are at capacity.
Some shops are still leaving the amount of people in store up to the discretion of managers, with Sainsbury's asking its workers to ensure everyone in store can stay two metres away from each other.
A spokesman said: "Wednesday 25 March, we are limiting the number of people in our stores and at our ATMs at any one time. This includes putting queuing systems in place.
"We ask customers to keep at a safe distance of two metres apart. From Thursday 26 March, we are reducing the number of checkouts in supermarkets, convenience stores and petrol stations."
Source: The Telegraph