Butterfly Conservation is a national charity devoted to looking after our fluttery friends. And it’s based right here, in Dorset. Faith Eckersall paid them a visit… DO the workers at Manor Yard in East Lulworth love a butterfly? Does Michelle Obama love a cardigan?

They are movingly and magnificently obsessed with every single one of our 56 native species, plus the 2,500 moths and occasional exotic blow-ins that roam our land.

And a good job, too. As CEO Dr Martin Warren explains, 50 per cent of British butterflies are threatened with extinction. And even when a species is common: “We sometimes don’t know how common that is!”

What they do know – thanks to the 10,000 volunteer recorders of lepidoptera (which makes us the number one butterfly information nation) – is that butterflies are one of the swiftest indicators of environmental change.

“They are so sensitive to change you can quickly detect what’s going on, well before it shows up in other species,” says Martin.

The key to conserving these beautiful creatures is in preserving their natural habitats. The charity’s job is rather like catering to the needs of a thousand diva-ish celebrities, with their incessant requirements for certain types of flower, on certain types of habitat, grazed or kept in a particular manner at a specific time of the year.

The Jennifer Lopez of butterflies must surely be the Large Blue, which requires wild thyme munched to a precise height so that a specific species of red ant – not just any old red ant – will cart its larvae inside their nest before it metamorphoses. But Butterfly Conservation perseveres because not to would risk a horrific fracture in the food chain.

“Birds eat moths so a plentiful supply are vital to the survival of many species,” says Martin.

“Take the rare nightjar, for instance. They swallow moths as they fly, which is why they have that big, gaping mouth.”

The biggest guns in the battle to save our butterflies are farmers.

And the good news for them is that to help, they just have to do less.

“We want them to leave patches of nettles and rough strips round the edges of their fields,” says Martin.

Hedges, he says, don’t need frequent trimming unless it’s for safety issues. And if they make a few tweaks to their patterns of grazing, they could be rewarded with an explosion of lepidopteric activity.

Butterfly Conservation has two important supporters in this aim. Firstly Marks & Spencer, which this week announced it would be actively working with its farmers to manage their land for butterflies.

And the other big gun is no less than Sir David Attenborough, Butterfly Conservation’s president.

“One of the enormous perks of this job is that I get to talk to Sir David,” enthuses Martin.

Martin could talk about butterflies all day and I could listen.

But the whole point of them is to see them and so we venture out, firstly to the official Moth Trap, where they collect and record their night-time visitors. We are rewarded with a Hawkmoth, one of the real characters of the moth world.

Martin gently removes the furry, sleeping creature as his colleague records the other visitors – a White Ermine, so-called because his wings resemble an outfit from the House of Lords, and a Footman.

Many of our moth and butterfly species weren’t named until as late as the Victorian era, which could explain the distinctly bourgeois perspective. We have everything from the Duke of Burgundy (disturbingly rare) to the Gatekeeper, Chimney Sweeper and the Red-Necked Footman.

Moths recorded, we travel to the sun-drenched slopes of Bindon Hill, above Lulworth Cove. As we move from the north to the south-facing slope, I notice spatters of yellow flowers at my feet – Horseshoe Trefoils – and over them flutter the Adonis Blue.

The biodiversity of this little patch of land is giddying, as is trying to keep up with Martin.

“Look,” he whispers, “it’s a Green Hairstreak.”

This iridescent beauty is smaller than my fingernail.

“Look at his lovely little face and his little striped socks,” Martin urges.

I do and he’s right – the butterfly looks like something out of Disney.

As we amble reluctantly back, Martin reveals one last, amazing butterfly fact.

They can see colours which don’t even exist to us. Imagine it. And then imagine a world without butterflies. Unthinkable.

• Join the Big Butterfly Count from July 24 to August 1.

For details click on to butterfly-conservation.org