A growing number of "alien" species, from killer shrimps to Spanish slugs, are threatening UK wildlife, the economy and even people's health, a report has said.
The bee-killing yellow-legged hornet is among the non-native species set to soon reach our shores, as the rate at which new species are being introduced to Europe continues to increase, the Europe-wide study warns.
The Asian hornet, which grows to between 2.5cm and 3cm (1-1.2 inches), preys on native honeybees, wasps and other pollinators, potentially devastating hives and threatening honey and crop production.
The report from the European Environment Agency (EEA) also warned of the spread of the Asia tiger mosquito, which is linked to more than 20 diseases including yellow fever and the dengue-like chikungunya fever.
The species is prevalent in several southern European countries, such as Italy, and is likely to expand its range north as the climate changes, the EEA study said.
Species which are already in the UK and causing problems include common ragweed, which came in to Europe from North America in grain mixes intended as bird feed and is a potent trigger for hayfever and other allergies.
The Spanish slug, which reaches up to 15cm (6 inches) in length and is possibly native to the South East, is now found across Britain, and can hit garden planting and horticulture, as they eat plants as well as carrion and even each other.
More recent arrivals include killer shrimps, which feed on other aquatic wildlife and can cause local extinctions of naturally found species and zebra mussels, thought to have arrived in ship ballasts and which can damage infrastructure such as water plants and locks.
Other species posing problems to the UK include brook trout, American bullfrogs, rhododendrons, Japanese knotweed, harlequin ladybirds and the horse chestnut leaf-miner moth.
Jacqueline McGlade, EEA executive director, said: "In many areas, ecosystems are weakened by pollution, climate change and fragmentation. Alien species invasions are a growing pressure on the natural world, which are extremely difficult to reverse."