A species of wasp never recorded before in the UK has been discovered at a nature reserve in Kent.

The parasitic wasp, a Lymantrichneumon disparis, was caught in a chance sweep of a butterfly net at the Royal Society for the Protection of Bird's (RSPB) Broadwater Warren reserve, near Tunbridge Wells.

Tony Davis, of the Butterfly Conservation, was undertaking a moth monitoring programme in 2013 when he came across the species.

It has taken two years to publish, but experts have now concluded the wasp has never before been recorded in the UK.

Mr Davis said: "I’d finished my work and was leaving the reserve but couldn’t resist one last sweep on my net and that’s when I found the wasp. I knew it was something special, but I could never have guessed it was an entirely new species to the country.”

The specimen was sent for identification to Dr Gavin Broad, an expert on ichneumonid wasps, employed by the Natural History Museum

"I’d finished my work and was leaving the reserve but couldn’t resist one last sweep on my net and that’s when I found the wasp" - Tony Davis

Dr Broad believes the find was a recent colonist from continental Europe. He said: “It’s not uncommon to find parasitic waspsnew to Britain, but to find a new genus for the country that is large and showy is very unusual and good evidence of change in our fauna.

"I knew almost immediately what this wasp was as I’d recently been looking at some Japanese specimens of Lymantrichneumon dispar. It was rather surprising to see one from Britain. Inevitably, it took me quite a while to publish on this.”

In Europe the wasp lives off a few related moth species including the gypsy moth, which has recently colonised parts of southern England.

It is possible that the arrival of the wasp is related to this gypsy moth colonisation. However, the wasps are known to parasitise native moths too, so its arrival could also be due to warming of the climate.

Broadwater Warren was acquired by the RSPB in 2007.