The World Health Organization (WHO) has said it is in "close contact" with UK officials over the emergence of a new variant of coronavirus.
The new variant is spreading more rapidly than the original version, but it is not believed to be more deadly.
Along with the UK, the same mutation of the Covid-19 virus has also been detected in the Netherlands, Denmark and Australia, the WHO told the BBC.
There is no evidence to suggest the new variant reacts differently to vaccines.
In the UK, large parts of south-east England, including London, are now under a new, stricter level of restrictions in a bid to curb the rapidly spreading virus.
On Sunday, the Netherlands introduced a ban on passenger flights from the UK until 1 January because of the new variant.
The move comes after tests carried out on samples taken in the Netherlands earlier this month revealed the same new variant of coronavirus as that reported in the UK.
Pending "greater clarity" on the situation in the UK, the Dutch government said that further "risk of the new virus strain being introduced to the Netherlands should be minimised as much as possible".
The Dutch government also said it would work with other European Union member states in the coming days to "explore the scope for further limiting the risk of the new strain of the virus being brought over from the UK".
Speaking to the BBC's Andrew Marr programme, WHO epidemiologist Maria van Kerkhove said that specialists had been "following mutations across the world since the beginning of the pandemic". (BBC)