Boris Johnson postponed the next stage of easing lockdown restrictions in England, due to begin today.
The return of casinos, bowling alleys, skating rinks, indoor performances and wedding receptions for up to 30 people will now be delayed until at least 15 August.
The prime minister also announced socially distanced pilots of sporting events with crowds and gatherings in conference centres will be postponed, as will be the reopening of close-contact services in settings like beauty salons.
From Saturday 8 August, face coverings will become mandatory in places such as museums, galleries, cinemas and places of worship in England.
Mr Johnson said the Office for National Statistics (ONS) had reported that the prevalence of the virus in the community in England was likely to be rising for the first time since May.
The ONS estimates there are now 4,900 new infections every day, up from around 3,000 per day on July 14 and 2,000 a day at the end of June.
Mr Johnson said he could not afford to ignore this evidence, and added that “our assessment is that we should squeeze that brake pedal in order to keep the virus under control”.
However, some measures are still being eased on Saturday across much of England.
This includes a pause in mandatory shielding by clinically extremely vulnerable people, who can now gather outdoors in groups of up to six people, while continuing to observe social distancing rules. This relaxation does not apply to Leicester, Luton and Blackburn with Darwen.
Mr Johnson also said the move to allow more discretion for employers with regard to staff returning to work will go ahead.
In Greater Manchester, East Lancashire and parts of West Yorkshire, the government said rising infections there means gatherings with people from other households in private homes or in their gardens would be banned.
Household mixing in public venues - such as bars and restaurants - in those regions is also strongly advised against by the government.
The new restrictions apply to Greater Manchester, including the City of Manchester, Trafford, Stockport, Oldham, Bury, Wigan, Bolton, Tameside, Rochdale and Salford.
They also apply to Blackburn with Darwen, Burnley, Hyndburn, Pendle and Rossendale in Lancashire, and Bradford, Calderdale and Kirklees in West Yorkshire.
Similar restrictions will also apply to Leicester, which saw the first so-called “local lockdown” imposed on 29 June.
What does this mean for the people living in the affected areas?
Government guidance published on Friday states that it will be against the law for people from different households (so, those who do not live together) to meet in a private home or garden, unless they are part of a support bubble.
Does this mean two households cannot meet up at all?
The guidance states that up to two households, or six people from any number of households, are allowed to meet outdoors - but not in people's gardens. It says people should continue to socially distance from anyone they do not live with and avoid physical contact.
On Friday morning Mr Hancock told the BBC that two households can still meet “at a social distance in a public place outdoors” such as a park, where there is lots of space, but meeting another household in pub gardens or outdoor restaurant space is not allowed in the newly restricted area of the North West.
Can people in the affected areas travel outside the affected areas and vice-versa?
Mr Hancock said people can still travel “for work purposes”.
He said: “Strictly, the law we're bringing in is that two households cannot meet in the area defined but obviously any two households who are meeting should follow the social distancing guidelines.”