Anglian Water workers have had to add looking after bats to their job description after a colony of the creatures set up home in their office.

Staff at the water company’s Beccles office in Worlingham were completely unaware the pipistrelle bats have been raising their young in the roof of the building until they started dropping through into the office.   

Matt Green was one of the first to spot the unusual visitors. He said: “About a month or so ago we were in the office at Beccles and there was a bat - a tiny little thing not much bigger than your thumb – in the middle of the floor.  

“We picked it up and put it outside under a tree and thought no more about it. Then, about two or three weeks later one of our technicians went in on the night shift and there were three of them flying around the office.  

“I went in the next day and there were another three on the floor.”  

Matt contacted Anglian Water’s biodiversity team, who in turn got advice from the Bat Conservation Trust.  

He said: “The advice was to use a box to keep them in during then day, so that’s what we’ve been doing. We put them into a little box with a dark fabric lining and leaving them in a dark room during the day before releasing them outside in the evenings.  

“One of our technicians has been given the job of collecting and releasing them. His name’s Jon but we call him Bruce Wayne now.”  

He added: “There’s clearly a roost and watching the building from outside in the evenings and we’ve seen 50 or more bats coming out.  

“We have tried to seal off the holes they are using to find their way from the roof into the office while leaving their entrance to the outside world clear. But we still get them coming in, although not as many.”  

Mike Drew, Anglian Water’s Biodiversity Scientist, said: “They’re most likely common pipistrelles.  

“We think they are moving around a lot more in the day because it is so hot and then finding their way in through little cavities. They can get through holes not much bigger than a fifty pence piece.  

“All bats are protected in the UK along with their roosts, so that roof space is protected until they move out. It looks like a maternal roost as there are so many in there.  

“They will go somewhere else around November to hibernate over the winter but they aren’t causing us a problem so we won’t block their access to the roof space when they leave.  

“It’s wonderful to have such a large roost on our site and we’ll certainly welcome them back next year.”  

Pipistrelle bats are among the species listed in Anglian Water’s field guide, which helps staff identify the species they are working alongside and how to manage their sites for wildlife.