The further easing of coronavirus restrictions in England – due to come in this weekend – has been postponed for at least two weeks, amid concerns over an increase in coronavirus cases.
Casinos and bowling alleys will remain shut, with Boris Johnson saying it was time to “squeeze the brake pedal”.
Wedding receptions of up to 30 people were meant to be allowed as part of the changes but cannot yet happen.
Face coverings will be mandatory in more indoor settings, such as cinemas.
And people attending places of worship will also be among those required to wear face coverings, in a change that will be applied from next weekend.
The rethink follows new restrictions for people in parts of northern England, after a spike in virus cases.
The prime minister said progress against coronavirus continues, with the daily and weekly number of deaths falling, but warned that some European countries are “struggling” to control it. The UK must be ready to “react”, he said.
Highlighting the latest figures from the Office for National Statistics, he added: “The prevalence of the virus in the community, in England, is likely to be rising for the first time since May.”
Mr Johnson said planned reopenings for 1 August would be delayed for at least a fortnight.
That means venues such as casinos, bowling alleys, and skating rinks must remain closed until 15 August.
Indoor performances will also not resume, pilots of larger gatherings in sports venues and conference centres will not take place, and wedding receptions of up to 30 people will not be permitted.
Separately, face coverings will be compulsory in more indoor settings where people are likely to come into contact with people they do not know, such as museums and places of worship, from next weekend. They are already required in shops and indoor transport hubs.
The prime minister said the rules for face coverings would become enforceable in law from 8 August.
The plan to pause shielding from Saturday will go ahead as planned, according to the prime minister. Some 2.2 million people have been self-isolating in England during the pandemic.
That means they can return to work, if they cannot work from home, as long as their workplace is Covid-secure.
Guidance for employers will also change as planned from the start of August, giving employers “more discretion over how employees can work safely, whether by continuing to work from home, or attending a Covid-secure workplace”, Mr Johnson said.
According to the ONS, there is “now evidence to suggest a slight increase in the number of people in England testing positive on a nose and throat swab in recent weeks”.
This is based on the organisation’s infection survey – taking swabs from people selected at random in homes in England.
Last week, the ONS estimated that there were 2,800 new infections each day and that one in 2,000 people – 28,000 in total – were infected in homes in England.
Areas included in announcement
Cases per 100,000 people