The 3mm-long micro moth, which lives in Hembury Woods in Devon, was recognised as a new species this year.
This week, the biologist who discovered it is presenting the Natural History Museum of London with one of the first known specimens.
The receipt of this "type" specimen will mark the official acceptance of the moth's existence in the country.
The tiny micro moth, which has a wingspan of just 6mm, was first spotted in 2004.
At that time, amateur naturalist Bob Heckford sighted the unusual bright green caterpillars of this tiny leaf-mining moth on oak saplings within Hembury Woods, a site managed by the National Trust.
In January this year, the moth was officially recognised in the journal Zookeys as a new species, named Ectoedemia heckfordi after its discoverer.
It is not known to live outside of the UK.
Now Mr Heckford is presenting the Natural History Museum with the original specimen.
That is important, because it marks the official acknowledgement by the scientific world of the specimen as the "type" for that species, against which any future finds will be compared and determined.
"We hear so much about the losses to the natural world, and less about the gains; which makes this find, however small, so important," says Matthew Oates, an adviser on nature conservation at the National Trust.
"Amateur naturalists have a wonderful window on the wildlife world and nature continues to amaze us and throw up surprises even in the UK."
There are well over 2,000 species of micro moth in the UK.
They come in various shapes and sizes, but many are extremely pretty, though only appreciated under magnification.
A few are actually larger than some larger, so-called macro moths.
Their biology varies.
Most are plant feeders, with larvae often mining galleries in leaves, between the leaf surfaces.
A few mine stems.
Some, though, breed in fungi and a few have aquatic larvae.
Most are nocturnal but quite a few also fly by day.
Caterpillars of the new species are found mostly on oak saplings and low growth of oak in the shade.
The mines they make are quite dark and the caterpillars are bright green which is quite unusual for micro moths.
The adults lay their eggs on the underside of the leaf.