Image copyright Getty Images Image caption Visits to stores will now be carefully regulated

Visit a supermarket today and you're likely to be greeted outside by a member of staff.

But they won't be helping you with your shopping.

Instead they'll be ensuring you stick to the new strict social-distancing rules that have applied since Monday evening.

At Waitrose you'll be met by a marshal, while at M&S they're called greeters. Asda will also station more staff at its shop doors to "greet" customers.

Their jobs are exactly the same: to ensure only a limited number of shoppers enter stores at any one time.

They also check people are queuing responsibly and that shoppers wait patiently and stand two metres away from each other.

Essentials only

Shopping is no longer a leisure activity.

Instead, visits to a store - which you're only supposed to make to pick up essentials - will be carefully regulated.

The rules are as much to protect store workers as shoppers.

Indeed, Lidl, Morrisons, Aldi, Iceland and Sainsbury's have all installed protective screens for staff, while Waitrose has ordered screens and visors for its workers.

Image copyright Aldi Image caption Aldi is one of the supermarkets installing protective glass

You'll see staff wearing gloves and plenty of hand-sanitisers near tills and other areas.

They also no longer want your cash. Instead, supermarkets are trying to encourage shoppers to pay by contactless card to cut down on potentially virus-covered cash being passed around the population.

You'll see posters encouraging you to look after yourself and treat staff well.

And on the floor, there are markings to show where it is safe to stand and when queuing.

At Sainsbury's, there's tape marking out the correct two metre distance to maintain between customers in a queue.

Tesco has lines on the floor and around checkouts to help shoppers with social-distancing measures.

Image copyright Getty Images Image caption Tesco has marked the floor to help shoppers keep their distance from one another

Online shopping

If you think you can avoid the new tightly-regulated in-store experience by getting a home delivery, you may be in for a disappointment.

Some people are having to wait weeks for an available slot as online systems struggle to cope with demand.

Visitors to online store Ocado on Tuesday were greeted with the message: "You are in a virtual queue to log in. Once you have logged in you may need to queue again to shop."

Samantha Ward, who went into self-isolation last week when her husband developed Covid-19 symptoms, is struggling to get any supplies.

"Every day since self-isolating, I've been trying to place an online shopping order with all of the main supermarkets but there have been no available slots for weeks ahead."

"Friends who have been going on shopping expeditions for me come back with very little," she reports.

"Supermarket shelves are stripped bare. But ironically, I'm regularly receiving standardised emails from the bosses of major stores reassuring me that there is plenty of food to go round!"

Image copyright AFP Image caption Some Ocado shoppers had to enter a a virtual queue to log in.

Extremely busy

There's also the Click+Collect option, where customers can arrange to pick up goods at their local store if they can't get a delivery slot.

But that can prove a problem too, as Maidenhead-based shopper Lisa Bull discovered.

"I booked a click-and-collect with Tesco as there were no delivery slots available. Throughout the week, I edited my order as I thought of things I and my self-isolating elderly parents needed.

"When I edited my order on Monday morning, I was then unable to check out and my whole shop was cancelled."

"It is an extremely busy time for both our stores and our delivery service and availability is challenging across many products," A Tesco spokeswoman told the BBC.

"We're doing our best to make sure people can get the food and items they need."

What are the new restrictions?

New guidance from the government says people should now only leave home for the following reasons:

Shopping for essentials such as food and medicine, with trips made as infrequently as possible

One form of exercise a day such as a run, walk or cycle. This should be done alone or only with people you live with

Any medical need, or to provide care or to help a vulnerable person. This includes moving children under the age of 18 between their parents' homes, where applicable. Key workers or those with children identified as vulnerable can still take their children to school

Travelling to and from work, but only where it absolutely cannot be done from home

Businesses that are allowed to stay open under the strict new guidelines include supermarkets, banks, pharmacies, post offices, corner shops or market stalls selling food and restaurants that offer a takeaway service.