A Cave Spider photographed by Anglian Water engineer Adrian Hinchcliffe

One of Britain’s biggest spiders has been found thriving on Anglian Water sites in Suffolk and Essex.

The cave spiders – Meta bourneti – have been found lurking in dark corners of several of the company’s water treatment sites near Ipswich, Colchester, Sudbury and Haverhill.  

The arachnid and its close relative Meta menardi can grow to be 30mm in diameter including the legs, making them some of the country’s largest spiders.   

Works Technician and keen wildlife photographer Adrian Hinchliffe comes across the spiders on his rounds and has managed to get some of the shy and retiring creatures to pose for the camera.  

He said: “We first noticed one on a float probe at our site in Great Wratting near Haverhill. We saw it was much larger than normal spiders so I took some pictures. We’ve found them on several sites since.  

“They are repelled by light and have to be in the dark, so they like our meter chambers, which are sunk into the ground.  

“Every now and then we have to inspect these chambers and lift the covers and see these rather large spiders. You have to break through the webs and you can see the tear-shaped egg sacs hanging down. It can be a bit daunting.”  

He added: “I think they are under recorded simply because they live in dark places people don’t go. Our teams are more aware when we open covers now and so we are increasing our records.”  

Steven Falk, Entomologist at invertebrate conservation charity Buglife, said: “These are mystery shrouded and spectacular spiders that do a great job of hiding from us, but are actually proving to be far more widespread than we had ever imagined. Open up a manhole cover or go into a deep canal tunnel and there is a good chance you will see a cave spider or its suspended egg cocoon.  

“We are getting increasing number of reports from water engineers in parts of Britain, many miles from caves. It makes you wonder how on earth they got there.  

“Fully grown ones have a leg span on par with a big house spider, but they are more closely related to garden spiders and cannot run very fast. They are totally harmless and females can probably live for several years”  

Their discovery on Anglian Water works has delighted the company’s biodiversity team, who make sure its sites are managed with their resident wildlife in mind.