It was more than 10 years ago that a chance pit stop by a UEA student insect scientist led to the discovery of a beetle haven off the A11 near Thetford.

It was more than 10 years ago that a chance pit stop by a UEA student insect scientist led to the discovery of a beetle haven off the A11 near Thetford.

On Saturday, the set-aside arable land farmed by a Norfolk family was named as the “best site in Britain” for a scarce ground beetle called Ophonus laticollis.

The striking metallic green insect has also been christened with the catchier name of Setaside Downy-back beetle in tribute to its ideal habitat at Croxton Hall Farm.

The site, near Gallows Hill, was first discovered by UEA student Mark Telfer on one of his regular commutes along the A11 from his girlfriend's London home to Norwich where he was taking a PhD on grasshoppers.

The land farmed by Gerald Goucher and his family has now become an important conservation area for the rare seed-eating bug after almost 20 years of leaving a six metre uncropped margin on his fields for the benefit of plants, insects and birds.

The second generation farmer, whose family has leased 1,200 acres from the Crown Estate for 60 years, said it was a “privilege” that the “nationally scarce” beetle was thriving on the land designated as an Environmentally Sensitive Area (ESA) for rare plants and invertebrates.

Mr Goucher, who says that he's never actually seen the green beetle, said: “It is really pleasing to see that this work has produced such good results. It is one of the extremely rare parts of the UK and I hope this very much slows down the rush for the development of Thetford with all these new houses. This shows that we need space for wildlife.”

The Setaside Downy-back is one of the rarest of Britain's 4,100 beetle species and thrives under thick hedgerows, weedy plants that produce lots of seeds, and light chalky soil.

Dr Telfer, now an entomological consultant (freelance insect adviser) based in Bedfordshire, said he could not believe his luck when he came across the habitat.

“When you drive up the A11 towards Norwich, there are fields on the left near Thetford that at certain times of the year are full of wild flowers and wildlife, which is what made me stop and have a look. Some places have a few of these beetles, but this is the best in Britain because they are really common there.

“It is a really nice example of how these arable margins actually work sometimes,” he said.

It is hoped that a survey to establish the exact numbers of Ophonus laticollis at Croxton Hall Farm will take place later this year. Officials from Natural England continue to work closely with Mr Goucher to secure the future of the beetle, which is in decline nationally as a result of the inappropriate management of mature hedgerows.

Bill Nickson, Natural England team leader for Breckland, said: “The land management at Croxton Hall provides exactly the right conditions for some Breckland species that thrive on light sandy soils. It is particularly gratifying to find that this land provides the UK stronghold for such a rare beetle.”