The Purple Emperor: One Of The Scarcest Butterflies in Britain Found In A Wood Ten Miles From Shepherd's Bush

"But spectacular though they may be, these are scarce and elusive insects. Only seldom does the casual naturalist see one, even in its strongholds of south Wiltshire and the western Weald."

That's what the essential The Butterflies of Britain & Ireland, by Jeremy Thomas & Richard Lewington, says about the Purple Emperor.

Patrick Barkham in the excellent The Butterfly Isles writes, "No other butterfly in Britain can compete with the charisma of His Imperial Majesty." This is a man who almost died of blood poisoning after getting bitten by a tick while on Emperor hunt. He eventually found 57 in Northamptonshire thanks to some judicious baiting.

So when a local wildlife expert tipped us off that a colony had been spotted in Ruislip Woods, an ancient bit of oakwood about a half-hour drive up the A40 from Shepherd's Bush, that was our Saturday sorted.

I'd never seen one before but knew from the guide books that their only rival in the British spectacular stakes was the Swallowtail - a butterfly we'd staked out in Norfolk earlier this year. But while the Swallowtail is obliging enough to glide down to eye-level flowers, the Purple Emperor prefers the neck-achingly high boughs of the oak trees where it lives.

But it didn't take long for Ruislip to deliver. Half-an hour of peering into the tree-tops was rewarded with the first high-up glimpses of a couple of unmistakeable butterflies. Even with the naked eye they were a striking sight - big enough to glide like birds with still-looking wings in the gaps between the leaves. A look through a telescope reveals their size and beauty in all their glory.

The eye-spot on the hind wing is clearly visible with the sun shining above the butterfly on the top photo.

As Jeremy Thomas says, "There are few greater thrills for any naturalist than to stand beneath an oakwood in high summer and watch male Purple Emperors soaring and wheeling above the canopy."

Especially when you can see them ten miles from the front door.

Another purple butterfly also brightened up an overcast Sunday afternoon in the garden. We'd seen a single Purple Hairstreak at Ruislip, but even though they're nationally very common, they're very unusual to find in W12 gardens, especially ones with no obvious oak trees in sight.

This one stuck around to feed on the buddleia just long enough for me to get a poor silhouette snap but tweaked on the computer it reveals that eye-spot on the underside next to the short tail - the only British hairstreak with those markings.

Well worth raising another outdoor glass of London Pride in its honour.