Delta Plus now accounts for more than half of cases analysed in one part of England, according to data analysed from the Wellcome Sanger Institute.
In Torridge in Devon, 50.3% of positive Covid tests that were genomically sequenced by labs were found to be the AY.4.2 strain, otherwise known as Delta Plus.
The data is based on Covid tests taken in the week to 13 November 2021.
Only a sample of positive cases are genomically sequenced in each area however, so there will be more cases that have gone undetected.
Across England as a whole, 36,829 cases were sequenced in the seven-day period, of which 5,304 (14.4%, or one in seven) were found to be Delta Plus.
These are the top 20 places in England with the highest proportion of Delta Plus Covid cases among those analysed.