Boris Johnson confirmed that the plans would go ahead last week, saying the lockdown-easing was "fully justified" - but urged the public not to be complacent.
Following is a list of everything that will reopen from today:
What businesses will reopen on April 12?
Non-essential retail.
Hospitality businesses (such as pubs and restaurants) with customers sat outside.
Personal care premises such as hairdressers and nail salons.
Public buildings, including libraries and community centres.
Indoor leisure facilities such as gyms (but only for use by people on their own or in household groups).
Most outdoor attractions and settings including outdoor hospitality venues, zoos, theme parks, and drive-in cinemas.
Self-contained accommodation such as campsites and holiday lets, where indoor facilities are not shared with other households.
What else can I do from today?
Parent and child groups of up to 15 people (not counting children aged under five years old) will be able to resume indoors.
The number of care home visitors will increase to two per resident.
All children will be able to attend any indoor children's activity, including sport - though soft play facilities will remain closed until step 3.
The number of people able to attend weddings, receptions and commemorative events such as wakes will rise to 15.
Next step of lockdown roadmap given go-ahead by Boris Johnson
When is will stage three of lockdown-easing start?
The earliest possible date for the next stage of lockdown is May 17.
However, Boris Johnson previously stated that all lockdown-easing would be subject to 'data not dates', saying that it will be depend on the following:
The vaccine deployment continuing successfully
There is evidence that the vaccine is effective in reducing deaths
There isn't a surge in hospitalisation
Assessment of risks are not fundamentally changed by new variants of Covid that cause concern
The third stage of lockdown will see pubs able to open indoors, and relaxed restrictions on gathering inside homes.