The Scientific Advisory Group for Emergencies said it cannot be sure that the current rate of infection is below one. The ‘R number’, as it is known, is as high as 1.1 in parts of the country but needs to be kept below one to maintain control of the virus. The release of the figures came as Boris Johnson announced the pausing on planned lockdown easing.
Parts of the north-west have already been placed in localised lockdowns and now the whole of Greater Manchester and east Lancashire are facing greater restrictions on rules.
The rate of coronavirus infection in the north west and south west has risen above one, the scientists advising the government have said.
In both the north west and south west, the growth rate of infections is at +1, showing the epidemic is speeding up in those areas.
Data released on Friday revealed the growth rate is now between minus 4 percent to minus 1 percent, compared with a rate of minus 5 percent to minus 1 percent per day, last week.
A growth rate between minus 1 percent to minus 4 percent means the number of new infections is shrinking by between 1 percent to 4 percent every day.
“However, we are starting to see early indications that these values may be increasing,” the report said.
“This is not yet reflected in these estimates because the data used to calculate R and growth rate reflect the situation from a few weeks ago.”
The figures for both R and growth rate are calculated using different models, with data gathered from multiple sources, such as hospital admissions and deaths, admissions to the intensive care unit, as well as epidemiological data.
A time delay between initial infection and the need for hospital care usually means it may take between two to three weeks for the changes in the spread of Covid-19 to be reflected in the estimates.
But models that use Covid-19 testing data, which have less of a time delay, indicate higher values for R in England, the Government Office for Science statement said.
It added: “For this reason, Sage does not have confidence that R is currently below one in England.
“We would expect to see this change in transmission reflected in the R and growth rate published over the next few weeks.”
Dr Daniel Lawson, a lecturer in Statistical Science at the University of Bristol’s School of Mathematics said: “The UK is clearly close to the tipping point in which the infection grows.
“Whether local lockdowns and other actions are enough is as-yet unknown. We should be prepared for further rapid action to prevent the infection from getting out of control again.”