The coronavirus reproduction number, or R value, across the UK is between 0.6 and 0.9, according to the latest Government figures.
But separate figures for Scotland and Northern Ireland show a higher calculation on the upper limit of 1 or more.
R represents the average number of people each Covid-19 positive person goes on to infect.
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 0.6 and 0.9 for the UK means that, on average, every 10 people infected will infect between six and nine other people.
An R number of 1 means that every person infected will pass it on to one person.
The latest growth rate for the UK is between minus 6% and minus 3%, which means the number of new infections is shrinking by between 3% and 6% every day.
R number and for the UK and devolved nations:
UK - 0.6 to 0.9England - 0.7 to 0.9 Scotland - 0.7 to 1.0Wales - 0.6 to 0.8Northern Ireland 0.9 to 1.1
However, the Government said a change in the lower or upper bound of the R value does not alone constitute a change in R or the growth rate.
The Department of Health and Social Care (DHSC) said: "If the ranges overlap between each week, this does not necessarily mean the R or growth rate has changed.
"A widening or narrowing of the range reflects a change in uncertainty."
It comes as the Office for National Statistics (ONS) released its Covid-19 Infection Survey that showed that estimated cases in England and Wales had reduced but there had been an increase in Scotland with cases levelling off in Northern Ireland.
The DHSC added: "While the epidemic continues to decrease nationally, there may be more variation in transmission locally within regions, with slower rates of decline in some areas and communities."
Currently all estimates of the R value for NHS regions in England are below 1.
R value and growth rates for regions in England:
England - 0.7 to 0.9 (-6% to -2%)East of England - 0.6 to 0.9 (-7% to -4%)London - 0.6 to 0.9 (-7% to -3%) Midlands - 0.6 to 0.9 (-7% to -3%) North East and Yorkshire - 0.7 to 0.9 (-6% to -2%) North West - 0.7 to 0.9 (-6% to -2%) South East - 0.7 to 0.9 (-6% to -3%) South West - 0.6 to 0.9 (-8% to -3%)
The estimates, overseen by the government's Scientific Advisory Group for Emergencies (Sage), are based on the latest data, available up to March 15, including hospitalisations and deaths as well as symptomatic testing and prevalence studies.