Record-breaking autumn temperatures attracted hundreds of rare moths to Britain in what experts have called the best migration of the insects in years.

A wide variety of species, usually found in the Mediterranean, flocked to Britain to bask in temperatures of almost 30 degrees Celsius (86 degrees Fahrenheit) and southerly winds.

Scientists from the Butterfly Conservation declared autumn 2011 as the best immigration season for more than five years.

Butterfly Conservation's Head of Moth Conservation Mark Parsons said: "This is beginning to look to be the best autumn for immigrant moths since 2006, both in numbers of scarce species and diversity."

The most significant immigrant may be the rare Flame Brocade, Butterfly Conservation said. Numbers of the purplish-brown moth with distinctive white wing flash are at their strongest for 130 years.

Experts believe there may be a colony of the insects living in Sussex.

Several species made famous by horror film "Silence of the Lambs", including the Death's-head Hawk-moth, the Crimson Speckled and the Vestal moth have also been drawn to Britain for the Indian summer.

The Spoladea recurvalis, an extremely rare tropical species, has been seen across the country.

"Prior to 2006 there had only been 19 records of this species in this country, with 19 recorded that year," Parsons said.

"More than 20 have been recorded so far this autumn, being found in Sussex, Dorset, Cornwall, Cumbria and the Isle of Man, additionally there have been the first records for Ireland."

Despite the recent boon, experts say 2011 has been a relatively poor year for Britain's rare moth species, which struggled as the result of an unseasonably dry spring.