The number of people who have tested positive for coronavirus in the past 24 hours has jumped by more than 4,300.
The total number of confirmed cases in the UK now stands at 385,936.
It comes as the UK death toll from Covid-19 rose by 27, bringing the total to 41,732.
The Government's Sage committee said the R rate in the UK has increased to between 1.1 and 1.4.
The R rate measures the number of people that one infected person will pass on a virus to, on average.
The higher R is above 1, the faster the epidemic is growing.
Large parts of England’s North West, West Yorkshire and the Midlands are now facing tough new restrictions, as Health Secretary Matt Hancock refused to rule out a second national lockdown.
Ministers announced a tightening of rules in response to "major increases" in Covid-19 cases, with Merseyside, Warrington, Halton and Lancashire (excluding Blackpool and Greater Manchester) escalated to "areas of intervention".
From Tuesday, residents must not socialise with other people outside of their own households or support bubble in private homes and gardens.
UK stays alerts during Coronavirus - In pictures
Restaurants, pubs and bars will also be restricted to table service only, while all leisure and entertainment venues including restaurants, pubs and cinemas must close between 10pm and 5am.
Mr Hancock said on Friday that a national lockdown is "the last line of defence" but refused to rule out the drastic step in tackling the rising rates of coronavirus.
The Health Secretary indicated that a two-week "circuit-breaker" shutdown is among options that will be considered if the surge in cases becomes “more out of control”.
Measures could include asking hospitality businesses to shut, and curfews on opening hours for some pubs and restaurants.
It comes amid reports that UK scientists have proposed for measures to come into force for two weeks in October, to coincide with half-term and avoid disruption to schools.
Mr Hancock said bringing back extensive restrictions like those imposed in March is "not the proposal that is on the table", but said nothing had been ruled out.
Asked about the possibility of a two-week national lockdown, Mr Hancock told Sky News: "What I would say is that we really do need to come together to tackle this. The virus is clearly accelerating across the country.
"We have got to take the necessary action to keep people safe."
Pressed again by presenter Kay Burley whether a two-week national lockdown was on the cards, he said: "We will do what is necessary to keep people safe.
"The last line of defence is for national action and I don't want to see that but we will do whatever is necessary to keep people safe in a very difficult pandemic."
