From Monday people will be breaking the law if they meet socially in groups of more than six. And they could be fined.

Prime minister Boris Johnson has urged people to limit their social contact “as much as possible” and to minimise interactions with other households as he outlined new measures to control a surge in coronavirus cases.

He said he was “sorry” that two households that exceed six people would no longer be able to meet in England from Monday, and said he wished that he did not have to take such steps.

But addressing the first Downing Street press conference since July, Mr Johnson said that “if we are to beat the virus then everyone, at all times, should limit social contact as much as possible”.

“It is safer to meet outdoors and you should keep your distance from anyone you don’t live with, even if they are close friends or family.

“So in England, from Monday, we are introducing the rule of six. You must not meet socially in groups of more than six - and if you do, you will be breaking the law.

“This will apply in any setting, indoors or outdoors, at home or in the pub.

“The ban will be set out in law and it will be enforced by the police - anyone breaking the rules risks being dispersed, fined and possibly arrested.”

Asked if Christmas was now effectively cancelled, Mr Johnson said: “Whether we are going to get things back to normal at all by Christmas, I’m still hopeful, as I’ve said before, that in many ways we could be able to get some aspects of our lives back to normal by Christmas.”

Mr Johnson also announced:

- Venues where people meet socially, such as pubs and restaurants, will be legally required to request contact details of every member of a party and retain the information for 21 days. Fines of £1,000 could be levied against hospitality venues if they fail to comply.

- Passengers travelling to the UK will need to fill out a simplified form with their contact details before they depart, while the Border Force will step up enforcement efforts to ensure compliance with quarantine rules.

- Plans to pilot larger audiences in venues later this month will be revised, and the government is reviewing its intention to return audiences to stadiums and conference centres from October 1.

- Opening hours of some venues could be restricted in some local areas.

- “Covid-secure marshals” will be introduced to help ensure social distancing in town and city centres in a bid to improve the enforcement capacity of local authorities.

The new rules follow a rise in cases from 12.5 per 100,000 people to 19.7 per 100,000 in the UK in the last week - with a particular rise in infections among young people.

Infections are most prevalent among the 19 to 21-year-old age group, with 54 cases per 100,000 people.

The uptick suggests the national R number is now above 1 - meaning the virus is spreading exponentially.

Mr Johnson also urged people not to book a coronavirus test unless they have symptoms or have been asked to book a test, following reports that people were being denied Covid-19 tests.

“We are increasing our testing capacity further to meet rising demand. You can help by only booking a test if you have a fever, a new continuous cough, or you’ve lost your sense of taste or smell - if you don’t have those symptoms and haven’t been asked to book a test, please don’t,” he said.