England's coronavirus R number has increased to between 1 and 1.2, worrying new figures show.
The rate represents the average number of people each Covid-19 positive person goes on to infect and last week it stood at between 1 and 1.1.
When the figure is above 1, an outbreak can grow exponentially but when it is below 1, it means the epidemic is shrinking.
An R number between 1 and 1.2 means that, on average, every 10 people infected will infect between 10 and 12 other people.
UK health officials today revealed that the epidemic could be growing by as much as 3% each day.
The current R rates per English region are; 1 to 1.3 in the North West, 1 to 1.2 in the East of England, London, South East and the Midlands, 0.9 to 1.1 in the North East and Yorkshire, and 0.8 to 1.1 in the South West.
It comes as scientists urged the Government to "pause" plans to ease England's coronavirus lockdown and issued seven demands amid a "rapid increase" in cases of the Delta variant.
The independent Sage panel warned that the latest data shows increased infectivity of the variant, also known as the Indian variant, and that it is spreading widely across the UK.
It made seven demands (scroll down for a full list) while suggesting England could go into a "full lockdown" again if the growth in cases is not reversed.
The mutant strain has become dominant in the UK and evidence suggests it may lead to an increased risk of being admitted to hospital compared with the Kent variant.
And a new study suggests the Pfizer-BioNTech vaccine works less well at preventing infections of the Delta variant.
Independent Sage said the link between Covid infection and hospitalisation "has not yet been fully broken" - despite claims by Health Secretary Matt Hancock - and the Government should delay its plans to lift restrictions on June 21 under Boris Johnson's four-step roadmap.
The group is chaired by Sir David King, the former chief scientific adviser to the Government.
Scientists said cases among children are "surging" and "spreading into the community", including those who have not yet received two doses of a vaccine.
A spokesperson for Independent Sage said: “We are currently witnessing a rapid increase in Covid-19 cases in England.
“Public Health England figures released on 3rd June suggest that the Delta variant has spread widely across the UK and is continuing to spread, that it has higher infectivity than the previous circulating variant, and that it is more likely to cause disease and hospitalisation.
