The welfare of an endangered bat population at East Devon District Council’s Knowle site could be in jeopardy if planned building works go ahead, say worried residents.

Experts have confirmed the site hosts what ‘could well be the largest population of the endangered lesser horseshoe bat in Devon’ and have expressed serious concerns.

They have spoken out ahead of the imminent sale of EDDC’s offices on the site, which have been ear marked for demolition to build a new retirement community.

However, the authority said it was aware of the existence of the rare creatures and the outline planning application for development had been amended accordingly.

The chairman of Knowle Residents’ Association, Keith Northover, said: “The residents are very upset and concerned at what appears to be the lack of consideration by the district council towards protected species.

“We need EDDC to come forward and say it is prepared to protect the park, wildlife and trees at Knowle.”

Ecologist and bat expert Louise Woolley said there was an estimated 170 of the species at Knowle.

She said: “It’s a major concern that the bats are taken into consideration in the design of any plans.”

She also said the woodland area on the grounds outside the roost was of primary importance to the animals and this was not necessarily covered by surveys.

Ms Woolley added: “We are very lucky to have a large proportion of the lesser horseshoe bat population. They are extremely rare and are given extra protection.”

In Britain, all bat species and roosts are protected, by domestic and international legislation.

Devon Wildlife Trust’s Peter Burgess said local authorities had a responsibility to ensure protected species were not negatively impacted by any development in the district.

An EDDC spokesman said reports on the bats had been included as part of the council’s outline planning application for Knowle, which was considered in March 2012.

He said this information had been passed on.

PegasusLife is the company hoping to develop the site.

The company’s public policy and planning director, Guy Flintoft, said any proposals submitted would be sympathetic to the wildlife and natural habitat on site and it would be guided by the appropriate authorities in these efforts.