Five of Britain's rarest butterflies are facing increased risk of extinction due to the washout summers of the last three years, a fresh study found.

In a study of more than 1,000 sites, researchers found that 2009 proved to be the worst year for Britain’s two rarest species viz. the Duke of Burgundy and Lulworth skipper.

Other rare species, including the wood white, the high-brown fritillary and pearl-bordered fritillary, have also suffered steep fall over the last three years.

It should be noted here that heavy rain makes it difficult for butterflies to fly. After wet summers of 2007 and 2008, previous year’s wet July and August affected butterflies adversely.

Speaking on the topic, Butterfly Conservation’s CEO Martin Warren said, “We've had this run of poor summers which have knocked these species down even further and they've got very little resilience to bounce back.”

Experts have warned that if the number of butterflies is declining then other wildlife will also be in falling.