A species of butterfly previously only found in Southern Europe has been seen in the UK for the first time, according to charity Butterfly Conservation.

Experts have tracked the Southern Small White butterfly's rapid expansion northwards through Europe over recent decades.

The first UK sighting was confirmed at Landguard Bird Observatory in Suffolk, after a volunteer managed to snap a photo.

It is not yet clear what has driven the species' expansion, though a warming climate is thought to be part of the answer.

Until recently, the range of the Southern Small White was limited to Southern Europe, in particular south-east Europe.