This means that non-essential shops and business have been ordered to close by the government.
The Prime Minister announced the third national lockdown in a televised address on Monday night.
However essential stores such as supermarkets are allowed to remain open.
MORE NEWS: McDonald's confirms which Portsmouth restaurants will be closed to customers in third lockdown | Full list of Gunwharf Quays stores and restaurants still open in Portsmouth during third lockdown
In the previous lockdowns, shops changed opening hours and introduced a number of safety measures as well as new rules and restrictions.
But will this be the same for the third lockdown?
We have pulled together a list of the opening times, rules and restrictions in place at the major supermarkets in Portsmouth over the coming weeks.
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5. Morrisons
Morrisons store in Portsmouth is open with its usual hours. From Monday to Saturday there is an hour for NHS workers between 6am and 7am. The in-store cafes are currently shut for dine-in. Customers also need to follow social distancing and wear a mask in store. The Sunday browsing hour is suspended. Photo: Google Maps
6. Aldi
Aldi in Portsmouth is open from 8am to 10pm Mon-Sat. There is a limit of three units per customer on toilet roll, pasta, flour and eggs. Customers have to wear face masks and follow social distancing when in Aldi stores. There is a traffic light system in place. Photo: Google Maps
7. Lidl
Lidl is open with its usual hours during the lockdown. It has a traffic light system to help you plan your next store visit. Customers have to wear face masks and follow social distancing. Also at the bakery there are tongs and disposable gloves available for use. There are also trolley cleaning stations. Photo: Google Maps
8. Co-op
Stores in Portsmouth are operating normal opening hours during the lockdown. Customers have to wear face masks and follow social distance. A traffic light system at the doors to show if it is safe for shoppers to enter, to limit the number of people inside at one time. Photo: Google Maps