England's chief medical officer has confirmed that a new mutant Covid-19 strain spreads more rapidly - and urgent work is underway to see if it is more deadly.
Prof Chris Whitty said the UK has informed the World Health Organisation about the new variant.
At the moment he said there is "no current evidence" to suggest the new strain causes a higher mortality rate or affects vaccines, but work is being carried out to confirm this.
Prof Whitty said: "As announced on Monday, the UK has identified a new variant of Covid-19 through Public Health England's genomic surveillance.
"As a result of the rapid spread of the new variant, preliminary modelling data and rapidly rising incidence rates in the South East, the New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG) now consider that the new strain can spread more quickly.
"We have alerted the World Health Organisation and are continuing to analyse the available data to improve our understanding."
