A butterfly once classified as extinct has been spotted in southern England according to a conservation group. Over recent weeks there have been multiple reported sightings of the Large Tortoiseshell Butterfly.

The butterfly has been spotted across Kent, Sussex, The Isle of Wight, Cornwall and Dorset. These sightings have caused the Butterfly Conservation to declare the species is now a breeding species in the UK, rather than a migratory one. It's the first time it has been ranked like this since the 1980s.

Professor Richard Fox, head of science at Butterfly Conservation told the BBC: "We don't know why the butterfly was lost from Britain, so it's difficult to know why it has come back as well, but it's likely to be the climate that is pushing those increased numbers across its European range and we are benefitting."

The butterfly is tree dwelling, and is larger than its relative the small tortoiseshell. The smaller butterfly lives in gardens and also has white dots on its wing tips that help set it apart from the Large Tortoiseshell.

The caterpillars of the Large Tortoiseshell eat the leaves from elms, willow, aspen and poplar trees.

According to The Guardian it was once thought that the spread of Dutch elm disease led to the decline of the Large Butterfly but now experts are of the opinion that the species was at the upper end of its natural range - and global warming is bringing it back to the UK.

This butterfly is not the first to return thanks to global temperatures rising. Higher temperatures have also been credited with continental moth species moving into, or being reestablished in the UK.

Butterfly Conservation has asked anyone who spots the butterfly to record it on iRecord - a free citizen science app. This will help to build a profile of where the butterflies are breeding.