Butterfly numbers fall after last year's cold summer

Dazzling: the small tortoiseshell butterfly (Getty Images)

Butterfly numbers fell by more than a fifth across the UK last year, a study has revealed.

The 22 per cent drop in butterflies is thought to be the result of an unusually cold summer and the ongoing deterioration of suitable habitat for the insects, wildlife charity Butterfly Conservation said.

The "wider countryside butterfly survey" involves counting butterflies in more than 700 random one kilometre squares across the UK.

A garden favourite, the small tortoiseshell, pictured, did particularly badly last year, with fewer than one butterfly seen per kilometre.

The common blue also struggled, with the butterfly spotted in only a third of the sites surveyed, compared to more than half in 2010.

And the once-widespread wall butterfly was largely absent from central England. The meadow brown was the most widespread and abundant butterfly, spotted in 80 per cent of surveys.