A flesh-eating worm from Argentina has wriggled its way into Britain - and is set to cause havoc for farmers and gardeners.
The killer creepy-crawly grows up to three inches long and has hundreds of tiny eyes along its whole body.
It hunts snails and earthworms - putting the UK's indigenous population at risk. The damaging pest could wipe out up to a fifth of our most vital invertebrates.
Ecosystems across Europe are under threat, warns a new study. Worms help to turn the soil, fuelling healthy plants as well as playing a vital role in the food chain.
The slimy brown flatworm, known as Obama nungara, was accidentally imported from South America and is now harming local wildlife.
It has spread rapidly throughout France adding to fears it has already crossed the English Channel in numbers - which will alarm the agricultural industry.
The crisis is being fuelled by the international trade in plants. Adult worms and cocoons can easily travel in pots.
The worm is now present in 72 out of 96 French metropolitan districts - an area representing 75 per cent of the country.
Lead Professor Jean-Lou Justine, a zoologist at the Natural History Museum in Paris, said: "To date, the presence of Obama nungara has been occasionally recorded from several countries in Europe, including Spain, Portugal, UK, Italy, and Belgium.
"However, in none of these countries has a study of the extent of the occurrence of O. nungara been performed."
The latest observations mainly by 'citizen scientists' are the first of their kind - and include 530 verified records received from 2013 to 2018.
Prof Justine said: "The extensive distribution of the species and its reported local abundance, combined with its predatory character, make Obama nungara a potential threat to the biodiversity and ecology of the soils in Europe.
"O. nungara is the most threatening species of all invasive flatworms present in Europe."
The inadvertent spread of invasive species by humans is one of the consequences of globalisation, said the team.
The worm was first seen in Europe on Guernsey in 2008, but has spread through France and into Spain and has also been confirmed at a number of locations in the UK.
It was first seen on the mainland in 2016 crawling out of soil from a Heuchera plant at a garden centre in Oxfordshire.
It has been found in at least two other garden centres and once in a private garden– suggesting it is gaining a foothold in the country.
The findings published in PeerJ suggests the problem is worse than first feared. It is the first comprehensive study of this invasion.
Prof Justine said: "The origin of the invasion by O. nungara is likely to be via the international trade of plants, since adult flatworms and cocoons can easily travel in potted plants."
This was the case for other foreign flatworms arriving in Europe including the New Guinea species, Platydemus manokwari, and the giant hammerhead from Asia, also reported in France.
Prof Justine said: "However, in contrast to the previously recorded species of land flatworms that have been found only in a limited part of the country, Obama nungara is reported from an area representing three quarters of metropolitan France."
Land flatworms are predators of soil animals, including earthworms and molluscs.
This endangers the biodiversity of native animals and soil ecology, although the extent of impact has yet to be analysed.
Prof Justine said: "The species is especially abundant in gardens along the Atlantic coast and the Mediterranean coast. The species has also been recorded on Corsica in the Mediterranean Sea.
"Most records were from a low altitude, and there are no records of the species from mountainous regions such as the Alps, Pyrenees and Massif Central. New records from Italy and Switzerland are also included in the study."
Molecular studies show Obama nungara has three populations - two in Argentina and one in Brazil.
Only one of these populations, from Argentina, is present in Europe. This includes all France as well as Spain, Portugal, Italy, Belgium, Switzerland - and the UK.
Prof Justine said: "The population from Brazil has not reached Europe; Argentina is the sole source of this invasive species in Europe."
He added: "It is expected this new paper will encourage new records of Obama nungara from members of the public, not only in France but possibly other countries."
It has been suggested O. nungara will reduce earthworm numbers in the UK by up to 20 per cent – judging by the experience with the invasive New Zealand flatworm.
Earthworms are essential for keeping soil healthy – both in gardens and in crops for agriculture.
Their loss makes soil less fertile and more prone to flooding as worms digging holes help drainage.
Obama nungara is just one of an 'avalanche' of invasive species threatening plants and animals in the UK because of 'feeble' controls of plant imports at our borders.
The importation of plants for gardens in the UK is a business worth more than one billion a year.
But few checks take place on the earth surrounding plant roots – for eggs or insects hibernating in the soil.
The charity Buglife has said there are a further 18 other species of flatworms that are rampaging in Europe. Lax controls on imports means they could easily spread into the UK.
The New Zealand flatworm first turned up in the UK, in gardens in Belfast, in 1963.