Single parents of children under 18 and adults who live alone will be able to form a “bubble” with one other household from Saturday, Boris Johnson has announced.
People will not have to socially distance from others in their bubble, and will be able to meet up indoors.
The prime minister made the announcement at the government’s daily coronavirus briefing.
Johnson said: “There are too many people, particularly those who live by themselves, who are lonely and struggling with being unable to see friends and family.”
He added: “Support bubbles must be exclusive, meaning you can’t switch the household you are in a bubble with or connect with other households.”
It comes after groups of up to six people were given permission to meet outdoors on Monday last week.
Johnson said that if any member of the support bubble developed coronavirus symptoms, all the members would have to follow the normal advice on household isolation.
He told the briefing: “We are making this change to support those who are particularly lonely as a result of lockdown measures.
“It is a targeted intervention to limit the most harmful effects of the current social restrictions.
“It is emphatically not designed for people who don’t qualify to start meeting inside other people’s homes because that remains against the law.”
Earlier on Wednesday, the Department of Health and Social Care confirmed that the UK’s coronavirus death toll had reached 41,128.
The figures cover people who have died in hospitals, care homes and the wider community after testing positive for coronavirus in the UK as of 5pm on Tuesday, up by 245 from 40,883 the day before.
Coronavirus: what happened today
Read more about COVID-19
How to get a coronavirus test if you have symptoms
How easing of lockdown rules affects you
In pictures: How UK school classrooms could look in new normal
How public transport could look after lockdown
How our public spaces will change in the future