Viruses mutate all the time and it's vital to keep a laser focus on whether the virus' behaviour is changing.
Why is this variant causing concern?
Three things are coming together that mean it is attracting attention:
It is rapidly replacing other versions of the virus
It has mutations that affect part of the virus likely to be important
Some of those mutations have already been shown in the lab to increase the ability of the virus to infect cells
All of these come together to build a case for a virus that can spread more easily.
It is thought the variant either emerged in a patient in the UK
or has been imported from a country with a lower ability to monitor coronavirus mutations.
Data from Nextstrain, which has been monitoring the genetic codes
of the viral samples around the world, suggest cases in Denmark and Australia have come from the UK.
The virus that was first detected in Wuhan, China, is not the same one you will find in most corners of the world.
The D614G mutation emerged in Europe in February and became the globally dominant form of the virus.
Another, called A222V, spread across Europe and was linked to people's summer holidays in Spain.