Two workers were successful recently in their claim of religious discrimination and constructive dismissal.
The case was brought against Prospects - a Christian voluntary organisation which was established in 1976 and provides support to adults with learning disabilities.
It introduced a recruitment policy under which it would only employ Christians, except for purely administrative roles, the Muslim News reports.
Ex-worker Mark Sheridan, who was a Christian, was instructed not to employ or promote non-Christians to non-administrative roles.
Meanwhile, his colleague Louise Hender was informed that, as she was not a Christian, she could not advance in the organisation.
Both staff members resigned over the issue.
Prospects claimed that Christianity was a genuine occupational requirement since workers were often required to provide "spiritual support" to adults who sought help from them.
However, during an employment tribunal, it was ruled that, while being a Christian was important, it was not essential. The charity therefore lost its defence.