The moth that is bonkers about conkers

It has withstood the threat of global warming - and of political correctness.

Experts are warning that the fruit of the horse chestnut, beloved of generations of schoolchildren, is in danger from the voracious leaf-mining moth.

The insects have already taken hold in trees in London and are beginning to rampage through the whole of the South-East.

A recent Forestry Commission survey found colonies in almost a quarter of the capital's 33 boroughs.

Andrew Halstead, principal entomologist at the Royal Horticultural Society, today said the effects of the outbreak could be devastating. "This is a really slow death for the trees. These insects will eat the leaves, which weakens the tree. Over a few years the tree will die. We already know the moth is found in several London parks and it has been in Wimbledon since 2002.

"Now we are starting to see it spread throughout the South-East. Just this week we discovered it in our gardens in Wisley in Surrey."

The leaf-mining moth has also been found in Hertfordshire and Oxfordshire. Mr Halstead added: "There is just no treatment for this, and it has no natural enemies."

He said they had no idea where the moth comes from, although it arrived in Europe in Macedonia in 1985. Experts at Kew say their trees have so far not succumbed to the bugs, but they are monitoring the situation.