The grey squirrel, despite being widespread across the majority of
mainland Britain, is not a native species of the UK.
As a result of this, they are one of the listed animals covered under The Invasive Alien Species (Enforcement and Permitting) Order 2019, part of this order makes it an offence to release grey squirrels into the wild, a point worth noting for anybody wishing to live trap a squirrel as any captured animals must be dispatched humanely.
Grey squirrels can cause significant damage to trees by stripping bark, wild song birds as they are known nest robbers of eggs as well as young chicks to eat and domestic and commercial properties by stripping insulation from wiring, tearing up fibreglass insulation to make dreys and some have been known to drown in cold water tanks.
Along with the damage they cause, grey squirrels are also known carriers of squirrel pox.