Hornets are much larger than the wasps that we are used to seeing in Britain (although they could be mistaken for a queen wasp - but this would only be in the early spring).
Yellow-legged Asian Hornets are usually seen "hawking", outside honeybee hives. Their prey is usually caught on the wing, with the Yellow-legged Asian Hornet hovering over the entrance to a hive and catching foraging honeybees returning with nectar or pollen. The hornet forces its prey to drop to the ground before paralysing it and carrying it away. In this way, the Yellow-legged Asian Hornet is reported to be capable of destroying up to 30 percent of a bee colony in just a couple of hours. Yellow-legged Asian Hornets may also enter a honey bee hive to raid a colony after attacking the honey bee guards.
As well as this distinctive behaviour, Yellow-legged Asian Hornets are slightly smaller than the native European Hornet and most of the abdomen is black except for the second-to-last band which is yellow - see below:
European Hornet below ↓
Yellow-legged Asian Hornet below ↓
Yellow-legged Asian Hornets also prefer to build their nests high in trees such as the one below: