Originally restricted to western parts of the United States and Canada, it managed to get to Italy in 1999 - presumably as a stowaway in a cargo of timber. Since then it has been following the migrant trail across northern Europe and made it to the UK in 2007. The majority of records have been of adults observed at light traps along the south coast of England, clearly indicating a large migration across the English Channel.
Adults and nymphs like to eat the flowers, developing cones and seeds of over 40 species of conifer trees, and they particularly like pine - including Scots pine. So no surprise to find it in Old Copse.
The Forestry Commission reckon it's not harmful, unless you are running a conifer seed nursery, in which case it can become a serious pest. So no need to alert the authorities. But I have logged a sighting with the Terrestrial heteroptera recording scheme, who keep records of invasive species.