Shirley Chaplin, Gary McFarlane and Lillian Ladele saw their discrimination claims rejected by the European Court of Human Rights in Strasbourg earlier this year.
Mrs Chaplin was switched to a desk job after she refused to take off a crucifix which hung round her neck, while Miss Ladele was disciplined by Islington council for refusing to conduct civil partnership ceremonies.
Mr McFarlane was dismissed from his role with the charity Relate after indicating he might have a conscientious objection to providing therapy to a same-sex couple.
The claimants attempted to take their appeals to the Grand Chamber of the Court but the judges have rejected their request.
Mrs Chaplin's claims were rejected on the grounds that the removal of her necklace was necessary to protect the health and safety of nurses and patients.
Appeals by Miss Ladele and Mr McFarlane were dismissed on the grounds that disciplinary proceedings against them were justified.
The ruling stated that both Islington council and Relate were bound by duties not to discriminate against their clients and meant they could not support staff who refused to work with homosexual couples.
Keith
Porteous Wood, executive director of the National Secular Society,
said: "Fortunately, Europe's highest court has now wisely followed
numerous lower courts and rejected the applicants' attempts for
religious conscience to trump equality law. The UK has the
world's most comprehensive equality laws which already include strong
protection for religious believers and they would have been fatally
compromised, particularly for LGBT (lesbian, gay, bisexual, transexual)
people, had the Grand Chamber overturned any of these judgments. We
hope that this will now draw a line under the attempts by a small
coterie of Christian activists to obtain special privileges for
themselves which would invariably come at the expense of other people's
rights. The principle of equality for all, including for
religious believers, is now established and they should stop wasting
the time of the courts with these vexatious cases."