A Somerset nature reserve which is home to a rare butterfly is being officially opened by wildlife presenter Mike Dilger, Butterfly Conservation (BC) can reveal.

Westbury Beacon is part of the scenic Mendip Hills near Wells, overlooking the Somerset Levels and an Area of Outstanding Natural Beauty (AONB).

BBC’s The One Show presenter and BC Vice-president, Mike Dilger, will open the new reserve to the public on Friday 5 August, after members of the wildlife charity managed to raise the £120,000 needed to purchase the site.

Butterfly hotspot Westbury Beacon boasts eight hectares of limestone grassland habitat which supports around 34 species, including the threatened Chalk Hill Blue.

This pale blue butterfly with silvery underwings has seen a 50% decline in its range across the UK in the last 40 years and its numbers are still falling.

Mike Dilger said: “As someone who lives in the shadow of the Mendips, I’m personally delighted that a lovely little parcel of limestone grassland close to my home has now been preserved for both nature conservation and the nation.

“Home to that delicious scrap of pale powdered blue that is the Chalk Hill Blue, I for one can’t wait to visit Butterfly Conservation’s newly acquired reserve, and trust (if you’ll pardon the pun) that the site will continue to be a 'Beacon of hope' for this marvellous, but sadly declining little butterfly.”

The new reserve is an important refuge for the Chalk Hill Blue in Somerset and Westbury Beacon is also one of the best places in the south west to see the butterfly, which is on the wing until September.

The butterfly’s caterpillar feeds on Horseshore Vetch and colonies are restricted to the chalk and limestone downs of southern England. The butterfly also has a remarkable relationship with ants, which protect the Chalk Hill Blue caterpillar through most of its life in return for sugary secretions.

Westbury Beacon is not only a haven for butterflies, but has a rich historical past and during the 1950’s and 60’s was used for radar testing and Cold War military observation.

A Neolithic standing stone and Bronze Age barrows can be found on the site, which is a short walk from BC’s Stoke Camp butterfly reserve and links with a series of other nature reserves and Sites of Special Scientific Interest (SSSI) in this key part of the Mendips.

BC’s Chief Executive, Dr Martin Warren, said: “I’m thrilled that we can now work together to connect these habitats, something that is vital for the survival of the Chalk Hill Blue and the other butterflies which depend on this landscape, like the Dark Green Fritillary and the nationally declining Dingy and Grizzled Skippers.

“Our Somerset & Bristol Branch has been keeping a close and concerned watch over Westbury Beacon for nearly a decade, but now we can finally begin the conservation work needed to protect all the wonderful wildlife this reserve has to offer.”