Asian longhorn beetle (ALB), Anoplophora glabripennis, are an invasive beetle species from China and Korea. They are especially dangerous to broad leafed trees, which they can devour in vast numbers.The beetle is large (2-4 cm long) but easily confused with other beetles that are not as dangerous (and are in fact British beetles essential to the woodland cycle).
Because of the dangerous invasive nature of this beetle any outbreak results in a local area ban on tree surgery and felling to insure all larvae and adults are destroyed and safely disposed of. We are all legally obligated to report any sightings of Asian Longhorn Beetles, so if you spot one, capture it in a jar (they are not dangerous, but can bite), and immediately report it. You can read more about the Beetle here on the forestry commission pages.