A poisonous moth capable of causing severe breathing problems and a measle-like rash has been spotted in Richmond Park.
In extreme cases allergic reactions to the lavae of the oak processionary moth could kill - prompting Wandsworth Council to urge any residents who spot the winged insect to contact them immediately.
Rising temperatures due to climate change and imported oak from the Netherlands is being blamed for the recent arrival of the moths in south-west London.
It is the moth's larvae which causes the most severe allergic reaction, and residents are warned not to touch them under any circumstances.
Even if the larvae are not handled the tiny poisonous hairs covering them can easily break off, become airborne and cause skin problems such as a measle-like rash, an unpleasant itch, conjunctivitis, an inflammation of the throat and asthma.
In very severe cases it could cause anaphylactic shock - which could be deadly.
The larvae construct communal nests of white silk from which they emerge as caterpillars at night in single file. They are named after their habit of forming nose-to-tail processions to feed on tree foliage.
In 2007, infestations of the moth in the Belgian province of Limburg became so serious that governor Steve Stevaert was forced to deploy soldiers to burn them.
A Wandsworth Council spokesperson said: "There's no need to panic, but these moths can cause unpleasant symptoms. They haven't been spotted in Wandsworth yet, but we would like to hear from anyone who has seen any evidence that the moth may be breeding in the borough.
"We would urge the public to keep an eye out and let us know immediately if they see a moth or a nest. That way, we can keep any potential outbreak under control."
The discovery adds to the list of unusual creatures recently spotted in south-west London.
Last summer a Sugar Glider was spotted in Wimbledon Common, over Christmas alien-like mussels were found in the Thames and recently the Harlequin ladybird has been displacing our native ladybirds.
If you have seen the oak processionary moth, its larvae or nests contact the council immediately on 020 8871 6144.
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