While cross-wearing BA employee Nadia Eweida enjoyed victory at the European Court of Human Rights (ECHR), three other Christians lost their cases, including hospital nurse Shirley Chaplin, who had been prevented from wearing a cross visibly around her neck.
They will be appealing today's judgment at the ECHR's Grand Chamber.
Speaking at a news conference in central London, Ms Chaplin said she was "very disappointed" by the judgment but heartened that other Christians can now wear a cross in the workplace.
She said she still feels that other religions are given more freedom in the workplace and called upon David Cameron to live up to a promise to change the law to protect cross-wearers.
The European Court of Human Rights has deemed a fair balance was not struck between British Airways check-in clerk Nadia Eweida's desire to demonstrate her religious belief with a "discreet" cross and the airline's wish to "project a certain corporate image".
The judgment, published in Strasbourg, found the airline's aim was "undoubtedly legitimate" but said British courts had accorded it "too much weight" in previous rulings.
Today's judgment is an excellent result for equal treatment, religious freedom and common sense. Nadia Eweida wasn't hurting anyone and was perfectly capable of doing her job whilst wearing a small cross. She had just as much a right to express her faith as a Sikh man in a turban or a Muslim woman with a headscarf.
British courts lost their way in her case and Strasbourg has actually acted more in keeping with our traditions of tolerance. However the Court was also right to uphold judgments in other cases that employers can expect staff not to discriminate in the discharge of duties at work.
– Shami Chakrabarti, director of human rights group Liberty
British Airways employee Nadia Eweida had argued the airline's denial of her wearing a cross contravened articles nine and 14 of the European Convention on Human Rights, which prohibit religious discrimination and allow "freedom of thought, conscience and religion".
Lawyers for the Government, which contested the claim, argued her rights were only protected in private.
But judges today ruled there had been a violation of article nine (freedom of religion), by five votes to two.
After being sent home in September 2006 for displaying the silver cross around her neck, Ms Eweida returned to work in customer services at Heathrow Airport's Terminal 5 in February 2007 after BA changed its uniform policy on visible items of jewellery.
European Court of Human Rights didn't rule religious symbols trumped corporate image. Wasn't convinced corporate image harmed in this case
He added that the ECHR judgment now means if an employer wants to prevent an employee from wearing a religious symbol for corporate image purposes, it must prove that its image has been negatively affected.
Cross-wearing British Airways employee Nadia Eweida, one of four Christians who say they were discriminated against in the workplace, has told Daybreak she is "very hopeful" of a win at the European Court of Human Rights, but is prepared to appeal if the judgment goes against them.
The 60-year-old check-in clerk from London said it was "very unfair" that she was prevented from wearing a visible cross necklace while at work.
Speaking ahead of the 9:00am judgment, Ms Eweida said: "I'm very hopeful of a win ... there is a saying: you get what you ask for. ... If we lose today, there is a possibilty we can appeal."
She also said some employers took advantage of those with Christian faith.
"It's a religion of love, that you turn your cheek," Ms Eweida added. "It's taken as weakness, so you're pounded on."