A DISCOVERY of a toxic caterpillar by a walker in Bromley has prompted the council to warn residents to stay clear.

After an original sighting in the grounds of the Royal Bethlem Hospital, the creepy-crawly was again spotted in several places around West Wickham.

The oak processionary moth caterpillar gets its name from the creatures' habit of forming long lines in trees.

There are now fears the pest - which poses risks to humans, animals and tress - could spread across London.

Each caterpillar has around 60,000 hairs which can be carried in the wind and contain a poison causing itchy skin rashes, irritation to eyes and a sore throat. Other, rarer, reactions include asthma attacks.

The insects also damage the trees they live on.

Forestry Commission south-east England director Alison Field said: "Large populations can defoliate whole oak trees by eating the leaves, leaving them weakened and less able to withstand other threats, so we need to control this pest to protect our beautiful oak trees as well as human and animal health."

Action is being taken by Bromley Council to remove any nests and residents are asked to report sightings.

Executive councillor for the environment, Colin Smith, said: "I would please urge everyone from residents in side-roads, through to country hikers to please be aware and report without hesitation, any possible sightings of this outbreak across the borough."

A specialist tree surgeon started removing the caterpillars from Bethlem Royal Hospital last Friday.

The oak processionary moth caterpillar

THE creatures were first identified in Britain in 2006 in west London and are thought to have been transported on trees from Europe used for a landscaping project.

In 2007, the situation got so bad in Belgium that the army was called in to incinerate the nests.

Residents should stay away from the caterpillars. If you do come into contact with them you should ring NHS Direct or your GP.

If you see a caterpillar or its nests, call Forest Research on 01420 22255 or email christine.tilbury@forestry.gsi.gov.uk If caterpillars are spotted on street trees in Bromley borough or on Bromley Council owned woodland, call 0208 313 4471.

People who are having oak trees pruned or felled in affected areas must contact the Forestry Commission’s plant health service for advice at plant.health@forestry.gsi.gov.uk or 0131 314 6414.

The NHS Direct number is 0845 4647, and health information is available from the HPA website, hpa.org.uk