The rare Chequered Skipper became extinct in England in 1976, but has now returned to its former stronghold by wildlife charity the Butterfly Conservation, which released the species in its former English stronghold at secret location in Rockingham Forest, Northamptonshire.
The reintroduction is part of the ambitious conservation project, Back from the Brink, in the hope the species will mate and lay the foundations of a new population of Chequered Skipper in England.
The project is attempting to save 20 species from permanent extinction, whilst benefiting over 200 more.
Back from the Brink Communications Manager, James Harding-Morris, said: "It will be a few years before we know how much of a success this introduction has been, but during that time Back from the Brink will be working to save hundreds of other threatened species."
The Chequered Skipper is traditionally a rare species, but it became extinct in England in 1976 due to habitat loss as a result of change in woodland management. These changes saw a decline in coppicing and an increase in confiner plantations which were uninhabitable for the butterfly.
Historically, the butterfly was found in woodlands and limestone grassland from Oxfordshire to Cambridgeshire and Lincolnshire.
Although the Chequered Skipper is found in areas of Scotland, conservationists have always wanted to reintroduce it to England if suitable habitat conditions could be replicated.
Reintroduction trials were attempted in the mid-1990s, with the data helping to provide vital information ahead of the recent major reintroduction attempt.
The Back from the Brink project has allowed Rockingham Forest to be restored to ideal conditions with wide, flower-filled rides.
Earlier this week, Butterfly Conservation ecologists travelled to Belgium to collect Chequered Skippers, where they are commonly widespread.
A mix of males and females were transported back to Northamptonshire where they were placed in release cages overnight.
This reintroduction is the first of several proposed reintroductions to take place across Rockingham Forest over the next three years, and it is hoped, it will enable the species to build a large, resilient and sustainable population of Chequered Skipper across the area.
Butterflies were taken from Belgium, rather than Scotland as the Belgian Chequered Skippers are found in a similar environment to Rockingham Forest and share the same caterpillar foodplant, False Brome.
The reintroduction is part of the Roots of Rockingham project which is working to restore the forest to its former glory. Many other woodland species are being helped, including the Willow Tit, Barbastelle Bat and the Lesser Spotted Woodpecker.
The project will be closely monitored to assess its success in the early stages, with the aim that in one or two years, once the population is secure, the public will be able to visit and enjoy seeing Chequered Skippers fly in England again.