An outbreak of toxic caterpillars that can cause asthma attacks, vomiting and skin rashes has descended on London, officials have warned.
Oak processionary moths (OPM), which are in their larval stage, have been spotted across the south-east of England and in the capital.
Hairs on the caterpillars can cause fevers and eye and throat irritations, the Forestry Commission said.
The organisation has issued a caution not to touch the species.
The biggest infestations of OPM were recorded in Greater London, stemming from Kingston upon Thames to Brent.
Some infestations were also spotted in Bracknell Forest, Slough and Guildford.
OPM caterpillars were spotted emerging from egg plaques in mid-April, and trees were later treated on 23 April, the Forestry Commission added.
“The treatment programme is expected to continue until late May or early June,” a spokesman said.