Caterpillars with toxic hairs capable of causing severe allergic reactions have been discovered in trees at Kew Gardens.

The discovery has seen garden bosses act immediately to stop an outbreak of the insects, which will develop into Oak Processionary Moths.

The insects have short hairs containing toxins which can be an irritant to lungs, eyes and skin and even cause severe allergies.

A spokesperson for Kew Gardens said: "There is currently no significant risk to visitors or staff and the situation is being closely monitored.

"The Royal Botanic Gardens, Kew, is working closely with organisations including the Forestry Commission and local environmental health officers to deal with this problem."

The problem is usually dealt with by spraying the nests with a hairspray-type product and then burning it with a blow torch.

A spokesman for the Forestry Commission said: "We only have a very short period before they start pupating to eradicate them.

"Once they are flying as moths they will be much more difficult to control.

"We are really urging people to report any sightings they have."

People should look out for the caterpillars (pictured above) or their silky webbed nests on tree trunks or hanging from branches.

The caterpillars tend to appear from the end of April and adult moths emerge between late July and September.

Their invasion into parts of West London has been blamed on climate change - the insects' natural range is the Mediterranean - and they are also now well-established in Holland, Belgium and Germany.

Anyone who finds a nest of Oak Processionary Moths should contact Richmond upon Thames Council's Environmental Health Department via email on commercialeh@richmond.gov.uk or by calling 020 8891 7994.

For more information and images visit the Forest Commission website, forestrycommission.org.