Many non-essential shops have already reopened, and now restaurants, pubs, hairdressers, outdoor gyms, and other venues will be able to join them from 4 July
So, what can customers expect?
What shops are open?
Shops in England, including those offering clothes, toys, books and electronics, are already throwing open their doors to customers again. Shops in Northern Ireland have reopened too.
Many have been announcing their plans:
- John Lewis is starting by opening 13 branches in stages
- Next is reopening just 25 of its 500 stores at first
- Debenhams is reopening 50 stores in England and three in Northern Ireland
- Marks and Spencer is reopening all its shops in England and Northern Ireland
- JD Sports is reopening all 309 of its stores in England
- Primark is reopening all 153 of its stores in England
- Argos, which has kept outlets in Sainsbury's stores open, is reopening 145 standalone stores for click and collect
- TopShop is reopening all its stores in England and selected ones in Northern Ireland
- Music retailer HMV is reopening 93 of its 113 stores
- Currys PC World is reopening 131 of its outlets
- Mobile phone operators are reopening too. Three UK is starting with 250 stores, Vodafone is opening 65 and EE is opening all its shops in England, while O2 has opened "some" shops
- River Island is opening 150 stores, with more to follow on Thursday
- Gap is reopening all its 81 shops in England
- H&M is opening "the majority" of its English stores
DIY, furniture and bicycle stores have also been reopening, following garden centres, open-air markets and car showrooms. Furniture giant Ikea opened 19 of its stores across England and Northern Ireland recently, prompting long queues.
Supermarkets, corner shops, banks, pharmacies and petrol stations stayed open during lockdown.
How will stores protect against coronavirus?
Shops which reopen must meet the government's Covid-19 secure guidelines.
These include showing customers they are aware of safety measures, putting protective coverings on large items like beds or sofas, and frequent cleaning of regularly-touched surfaces.
Perspex screens at the tills and floor markings to keep shoppers 2 metres (6ft) apart had become a regular fixture. But this 2m-metre rule has now been reduced to a minimum of 1m.
But some more unfamiliar measures - including pleas not to touch items unless you intend to buy - have been announced by some other shops.
For example, John Lewis will clean baskets after each use, and will not let customers use fitting rooms. Services such as personal styling, the bureau de change and food and drink outlets will be closed.
Marks & Spencer will also not be offering all of its services, such as its bra-fitting service, for example.
All the staff at Next will wear plastic visors, with the option to also wear masks if they want to.
Waterstones says it will quarantine books for 72 hours after people have touched them. River Island says it will do the same with items of clothing,
Currys PC World says only 42 of its shops will be fully open from Monday, with full browsing access for customers. In another 89 outlets, shoppers will be able to request products at the entrance and have them collected by staff.
Some shops, including Three UK and River Island, will have reduced opening hours to begin with.
H&M says it will make customers use different entrances and exits, while only a limited number of people will be allowed in at any one time.
Can I shop with friends?
Stores have been asked to encourage people to shop alone.
Big retailers have been urged to talk to local authorities about providing extra parking and bike racks where possible, to stop people using public transport.
The number of customers in stores will be limited, while shopping centres have been told they are responsible for controlling queues in common areas outside stores.
What about the rest of the service sector?
A reduction of the 2m distancing rule to what the prime minister called a "1m-plus rule" means many businesses in England have been given the green light to reopen from 4 July.
Pubs and restaurants can start serving customers indoors, although it will be limited to table service only. Hairdressers can reopen, but staff must wear visors.
Museums, hotels, cinemas, camping parks and outdoor gyms are among other areas that can also reopen provided safety measures are in place, such as distancing.
But nightclubs, swimming pools, indoor gyms and casinos are among sectors that will remain closed.
What about the rest of the UK?
In Northern Ireland, all shops are now allowed to open.
In Scotland, First Minister Nicola Sturgeon has announced that smaller shops and outdoor markets will be allowed to reopen from 29 June in phase two of the country's lockdown-easing plan.
Shops of all sizes will be able to open from that date as long as they have outdoor entrances and exits. Indoor shopping centres will remain closed, except for essential retailers such as supermarkets and pharmacists.
Prime Minister Boris Johnson said in his latest easing measures that he expects Wales, Scotland and Northern Ireland to continue "responding at their own pace".
How busy has it been?
The British Retail Consortium (BRC) predicted that it may take time for customers to return to their old shopping habits.
It estimated that the lockdown has cost non-essential retailers £1.8bn a week in lost sales.
However, there were queues outside some Primark shops in London and Birmingham before their 08:00 BST opening times. And the Birmingham branch opened its doors 35 minutes early to satisfy the demand.
Queues also formed outside shops such as TK Maxx and Foot Locker in the centre of Manchester.
With many people fearful for their jobs, now may not be the time to splurge on the High Street - but there may be bargains.
Clothing retailers went into lockdown just after stocking up with spring and summer ranges, which they now need to shift.