A US fad for using live butterflies as an exciting alternative to confetti is spreading to Britain, despite the complaint of butterfly experts that is cruel and environmentally damaging.

Instead of pouches of rice or paper, wedding guests are handed small decorated envelopes to open at the climactic moment. Inside are butterflies, which are supposed to take off in a multi-hued blizzard.

According to the Florida Monarch Butterfly Farm, one of the leading companies in the business, the practice has its roots in an 'Indian legend'.

Its website states: "If anyone desires a wish to come true they must first capture a butterfly and whisper that wish to it. Since a butterfly can make no sound, the butterfly cannot reveal the wish to anyone but the Great Spirit who hears and sees all."

The Butterfly Celebration, a Milton Keynes subsidiary of a US company, Insect Lore, now offers a "live butterfly release set" of the painted lady species for special occasions.

In the US a minimum order of 50 butterflies costs $200 (£140), and orders must be received a month in advance, to allow a consignment to be hatched and ready for shipment as adults.

The Florida Monarch Butterfly Farm advises customers to keep them in a cool, dark place to "keep them calm". It also says: "Butterflies released at funerals can be very therapeutic to the mourning process."

However, the North American Butterfly Association has criticised the practice, saying: "Butterflies raised by unregulated commercial interests may spread diseases and parasites to wild populations, with devastating results."

But on the website, Insect Lore's president, Carlos White, argues that released butterflies are more likely to be infected by wild ones. "In a world where Nature seems to be disappearing all about us, attempts to bring it ever closer to our lives should be rewarded," he states.