A rare breed of bats have been discovered roosting nearby a listed building currently being considered for redevelopment.

Five different breeds of bat were identified on the grounds of 11 High Street in Stevenage by the Herts and Middlesex Bat Group (HMBG), including rare UK breed Nathusius’ Pipistrelles.

Plans were submitted to Stevenage Borough Council (SBC) in February to convert the residential property into a 30-seater bistro restaurant.

Nearby residents have previously gather outside the building, situated opposite the Bowling Green, to protest the plans amid fears it would cause a noise disturbance and are now citing the wildlife discovery as reason for the development not to be approved.

Neighbour Richard Everett, who lives at the Old Coach House which backs on to the property, said: “There was already opposition to these plans but this has just reinforced our position.

“Two roosts have now been confirmed, leading to neighbours defending the bats against developers who are trying to convert the building into a restaurant – we don’t feel it is the right thing to do. Finding the bats in Stevenage is significant because of their rarity and bat specialists are excited by the discovery.”

A spokesman for HMBG said: “We are always working to further bat conservation in and around Hertfordshire. One species recently became extinct in Britain and others are now seriously endangered. May is a busy month for bats – particularly females who are finding suitable nursery roosts and establishing their maternity colonies.”

The plans are set to be discussed by SBC’s planning committee by June.