The approaching summer will be the best for butterflies in 30 years thanks to the warm, dry weather, conservationists are predicting.
Many species are emerging from their cocoons up to seven weeks early which means there is more time for them to have multiple broods.
A spokesman for the National Butterfly Fanciers' Club said: "Multiple broods mean each generation can gain strength and produce stronger offspring in spectacular colours.
"August will be peak time with around 40 species in flght... it will be the perfect time to sit, watch and get closer to the magic of butterflies."
But Prof David Attenborough, a head of zoology at Maidenhead University, and no relation to the celebrated TV naturalist, warns that a butterfly boom will prove dangerous for the public.
"Blimey! If this is right it's going to be a terrifying summer," he said. "All those butterflies flapping around - they're going to get nasty and probably start attacking.
"I would suggest that adults are in no danger, althouh they could still get a nasty bite, but we should keep an eye on small children and pets - and even if it's a lovely day, don't leave baby out in the garden unattended.
"Flocks of butterflies can strip a small animal of its flesh in seconds. Nasty little bastards - especially the cabbage white. In fact, if you see a cabbage white in your garden, call the authorities at once!"