Wales and England are estimated to have a roughly similar R number at the moment.

The latest advice from the Welsh Government's technical advisory cell estimates the R rate in Wales to be between 1.1 and 1.4.

The latest estimate for England put the figure at between 1.2 and 1-4. Even though large parts of the north of England have incredibly high rates of Covid (Liverpool is over 800 cases per 100,000), there are also huge swathes of southern England and the south west which have very low amounts of coronavirus.

Over the summer it was very hard for experts and modellers to come up with an exact R number because there was so little of the virus in circulation.

However, it has now reached the point where the virus is so widespread that experts are now able to say with more certainty what the R rate is in Wales.

The Welsh Government technical advisory cell said: "Currently we estimate the total number of infections in Wales is around 2,554 infections per day. Incidence has increased across all age groups, and is highest in those aged under 50."

It also said that "availability of testing may also be a constraint" on calculating the R rate amidst a UK-wide shortage of tests due to backlogs in the UK Government funded (but privately run) Lighthouse Labs.

The R number represents the amount of people each person with Covid-19 is infecting with the virus.

If that number goes above one, the number of people becoming infected with the virus will grow exponentially, but as long as it remains below one, the number of people infected with the virus will continue to fall.

Even if the R rate is falling, any figure above one means the cases of the virus are on the rise.

Find out how many cases are in your area

What about the rest of the UK?

The Department of Health in England publishes the R number for every region once a week.

Scotland has a current range between 1.2 and 1.5.

The estimated range for the R rate in Northern Ireland is between 1 to 1.3.