There are many species of plants and animals at large in the UK which are non-native. Yesterday, we discovered one growing around the lake at Straw's Bridge. A small, bright-yellow flowered plant, growing in the wet soils by the lake. It took some looking up trying to identify it, but eventually I discovered it is a Buttonweed (Cotula coronopifolia).
Next, an invader which has been getting much publicity of late. The Harlequin Ladybird (Harmonia axyridis). In this case the variety 'succinea'.