Phytophthora pluvialis was discovered in a woodland in Cornwall in September 2021, where it was found to be affecting mature western hemlock and Douglas-fir trees. Following extensive surveillance, further outbreaks have been found in Cornwall, Devon and Cumbria.
Phytophthora pluvialis meets the criteria to be classified as a GB quarantine pest for regulatory purposes and as such the Forestry Commission has introduced demarcated areas around the confirmed outbreak sites, and introduced movement restrictions on materials capable of spreading the disease.
You can read more and download the demarcated area map here-
https://www.gov.uk/guidance/phytophthora-pluvialis#reporting-sightings