The coronavirus R rate in the UK has increased to between 1.1 and 1.4, the Government's Sage committee has said.
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.
It comes as Downing Street has rejected claims that people are not able to get coronavirus tests in some areas of the country.
Despite widespread criticism over delays in getting tests, the Government insisted the system is working.
Asked about testing levels, a Downing Street spokesman said: “We are ramping up capacity, or working to ramp up capacity in terms of tests.
“I am not aware of anything to suggest that tests are not available in some parts of the country.”
On the tracing front, new data has shown that only a third of UK adults visiting indoor places such as restaurants or hairdressers are being routinely asked to provide personal details for Test and Trace purposes.
A report from the Office for National Statistics (ONS) said that 31% of adults in England said that they were always asked for their information, but over a quarter (27%) were never asked.
The survey of 1,130 adults across the UK, conducted between September 9-13, asked people how often they had been asked for their details when visiting places outside their homes in the past seven days.
Figures varied across different countries in the UK, with 45% of adults in Wales reporting being always asked for details and 66% in Scotland.
In Wales, 23% of those surveyed said they had never been asked and in Scotland the figure was 12%.
Meanwhile, large parts of England’s North West, West Yorkshire and the Midlands face tough new restrictions as the Health Secretary refused to rule out a 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, the following restrictions will be enforced in these places:
– Residents must not socialise with other people outside of their own households or support bubble in private homes and gardens.
– Restaurants, pubs and bars will be restricted to table service only, while all leisure and entertainment venues including restaurants, pubs and cinemas must close between 10pm and 5am.