4pm: The PM is expected to start his address shortly.

1. 03pm. Chief medical officer Chris Whitty is speaking. He displays a graph that shows that rates of new infections in older people and younger children remain "quite flat".

But there has been a sharp rise in new cases among the 20-29 age group. He said the increase was "really quite steep".

Mr Whitty said: "We're following a pattern extremely similar to what France followed. And as you can see in France, that rate has continued to go up, as it has in Spain."

4.09pm. Boris Johnson speaking.

He stresses the need for people to keep good hygiene, wear a face mask and keep a distance from people outside of your household.

"We are increasing our testing capacity further to meet demand," Mr Johnson says.

"I know that over time the [social distancing] rules have become quite complex and confusing," he says.

"We're simplifying and strengthening the rules, making it easier to understand and for the police to enforce.

"It's safer to meet outdoors and you should keep your distance from anyone that you don't live with.

"In England from Monday we're introducing the rule of six. You must not meet socially in more than groups of six and if you do, you will be breaking the law.

"This will apply in any setting indoors or outdoors ... anyone breaking the rules risks being dispersed, fined and possibly arrested.

"This single measures replaces both the existing ban on gatherings of more than 30 and the rule for people of two households to meet.

"There will be some extemptions. If a household or support bubble is more than six they can still gather.

"Hospitality venues can still hold more than six in total. Within those venues, however, there must not be groups larger than six and groups must not mix socially and form larger groups."

Organised sport will still be able to proceed. Weddings and funerals will have a capacity of up to 30 people.

"I would like to thank the police as always and other authorities for the work they're doing to keep us all safe.

"Premises and venues where people meet socially will be legally required to request the contact details of a member of every party, record and retain these details for 21 days and provide them to NHS Test and Trace without delay where required.

"Fines will be levied against hospitality venues that fail to ensure their premises remain covid-secure."

"I want to be absolutely clear, these measures are not another national lockdown.

"By bearing down on social contact and improving enforcement, we can keep schools and businesses open in the knowledge that they are covid-secure.

"As the chief medical officer and chief scientific advisor have said, the long-term risks to children's life changes of not going to school are far greater than the health risks of going back. Indeed, it's been fantastic to see so many children going back to school this term."[.b]

Prime Minister Boris Johnson is holding a press conference this afternoon on changes to the number of people who are allowed to meet.

Gatherings of more than six people in Richmond will become illegal under a tightening of restrictions, following fears of a spike in the number of new Covid-19 cases.

Mr Johnson is expected to explain the new rules at 4pm today (Wednesday, September 9).

What are the current rules

Social distancing guidelines already advise people not to meet outdoors in groups of more than six people.

But the law allows for general gatherings of up to 30 people.

This will be tightened from Monday, September 14 to make it easier for police to enforce the guideline and disperse large groups.

Activities that will be restricted and exemptions

The new limit is expected to simplify the current rules as it will apply to a majority of indoor and outdoor gatherings, including in pubs and parks.

Safely organised sports matches, weddings, work, schools and funerals will be exempt.

Mr Johnson told the press ahead of his press conference: "We need to act now to stop the virus spreading.

"So we are simplifying and strengthening the rules on social contact – making them easier to understand and for the police to enforce."

We'll provide updates at the top of this page, so stay tuned.