The Government believes the South West's coronavirus R number and growth rate could be higher than anywhere else in the UK.
In the region, the R rate is believed to be between 0.9 and 1.6, which means on average every 10 infected people will infect between nine and 16 other people.
The potential figure of 1.6 is higher than that of any other region of the UK, according to the Government figures released today (September 18).
The highest elsewhere is 1.5, in the Midlands and North West, where several areas have entered local lockdown.
If the R is above 1.0, it is expected to grow exponentially.
And the South West's growth rate is estimated to be between zero per cent and plus nine per cent, meaning the number of new infections is growing by between zero per cent and nine per cent every day.
The South West's potential figure of plus nine per cent is higher than the growth rate of any other region.
The next highest potential growth rate is plus eight per cent in the Midlands, North West, and North East and Yorkshire.
It means the South West's R and growth rate are both believed to have increased since last week, when R was estimated 0.9 to 1.2, and growth rate between minus one per cent and plus four per cent.
In the UK as a whole, R is believed to be between 1.1 and 1.4, while the growth rate range is plus two per cent to plus seven per cent.
The Government Office for Science says "the most likely true values are somewhere towards the middle" of the ranges given in these figures.
And the UK's scientific advisory group SAGE said: "When the numbers of cases or deaths fall to low levels and/or there is a high degree of variability in transmission across a region, then care should be taken when interpreting estimates of R and the growth rate.
"For example, a significant amount of variability across a region due to a local outbreak may mean that a single average value does not accurately reflect the way infections are changing throughout that region.
"It is SAGE’s expert view, however, that this week’s estimates are reliable, and that there is widespread growth of the epidemic across the country.
"These estimates represent the transmission of Covid19 over the past few weeks due to the time delay between someone being infected, having symptoms and needing healthcare."
Until last week, the Government released these figures with the caveat that case numbers are too low for the R or growth rate to inform policy decisions.
This caveat was not included in last week's or this week's release of figures, which could mean local lockdown measures are possible in any region.
In the latest daily figures, all four areas across the Bristol region saw new cases, Public Health England confirmed yesterday.
South Gloucestershire saw a rise of 17, Bristol seven, North Somerset seven and Bath & North East Somerset eight.
