This enigmatic butterfly was once a common insect in the 19th century in Hampshire, being found in the New Forest, along the coast to Portsmouth and up into the Ashford Hangers.

Until the early part of the 20th century it also occurred throughout much of the UK, then became intermittent into the 1920’s then it rallied in the 1940’s, before falling into obscurity. Entomologists believed that the demise was through attacks by parasites on the gregarious feeding larvae on its foodplant Elm.

Once quite common in the New Forest, it was found around keepers’ cottages in the Inclosures in the 19th century. It’s host trees Sallow especially (caprea) and Elm were much more common in the rides before the advent of the first world war.

Frohawk, a famous butterfly Entomologist is quoted as saying that it was common in the New Forest in 1893, when collecting was commonplace, with the taking of larvae around its favourite trees making it very easy to take the caterpillars or larvae at various stages. The Beaulieu Road Hotel was regularly plundered, as the Elms there were always covered in its larvae.

In the years of 1928-1931 it became uncommon in the forest; it disappeared along the coast towards Portsmouth. It was more common between Salisbury and Southampton in the late 1940’s. Then, in the Chilcomb area of the Test Valley, and over towards the Ashford Hangers, in and around the Petersfield in the early 1970’s and 1980’s.

In Hartley Wood and the Oakhanger woods in 1977 it was seen near some wild Cherry trees and at Wick Wood, and Cobden Copse Blacknest in 1984.

Dutch elm disease (DED) first appeared in the north-west of Europe about 1910. Between 1914 and 1919 several Dutch scientists carried out influential research on the cause of the disease. Then in the late 1920s Dr Tom Peace of the British Forestry Commission began to monitor its rapid spread to the United Kingdom.

This coincided with the rapid disappearance of the Large Tortoiseshell butterfly along with the White-Letter Hairstreak to a lesser degree, which can survive on Wych Elm growing along hedgerows. But this begs the question why the Large Tortoiseshell became extinct, even though it is known to breed on Sallow, Cherry and other fruit trees.

It has been seen on and off in several locations, along the coast in 1990’s and 2000’s especially, in and around Havant, north of Portsmouth. This area is covered in Elm Trees along the roadside verges and in the grounds of Queen Alexandra Hospital at Cosham. I suspect it could utilise these trees for breeding as there are colonies of White Letter Hairstreak there. Although so far as I understand it there hasn’t been any sighting yet of egg laying females or larvae feeding on Elm in this area.

Global warming may well be the kick start of its return to the UK, as there were more sightings in the 2010’s and 2020’s. There has been an influx from the Continent, especially from Holland and France.

On the Isle of Wight, in 2025/26 the Large Tortoiseshell has done well in the early spring months, and was also reported from Dorset, Hampshire, East and West Sussex, and a large influx in Kent.

The summers have been warm and the winters very mild which should favour this insect to become the UK’s 60th species once again.