Scientists have warned that the highly contagious UK variant of COVID-19 has mutated again and may give the virus the ability to evade the immune system.

Public Health England reported that some sample tests detected genomes with the E484K mutation, which has been seen in the highly contagious South African and Brazilian variants of COVID-19.

Calum Semple told  BBC  radio that this mutation is of “most concern” and seems to have developed spontaneously in the UK varient.

“The mutation of most concern, which we call E484K, has also occurred spontaneously in the new Kent strain in parts of the country too,” said Professor Semple, a member of the Scientific Advisory Group for Emergencies (SAGE).

UK Health Secretary Matt Hancock said that a further 11 cases of mutations of concern had been identified in Bristol and 32 in Liverpool.

Authorities in parts of London, the West Midlands, East, South East and North West England have started offering door-to-door and mobile COVID-19 testing in a push to test 80,000 people for the mutation.

“In all these areas it is imperative that people must stay at home and only leave home where it is absolutely essential,” Hancock said.

Testing is being offered to everyone in these areas over the age of 16, even if they have had the vaccine.

“The message is more important than ever to stay at home, maintain social distancing and get tested,” Hancock explained.

“We must all keep at it, we’ve sacrificed so much,” he added, warning of “difficult weeks ahead”.