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.
Barrister Adam Wagner, who specialises in human rights, has played down the wider significance of BA worker Nadia Eweida's victory at the European Court of Human Rights (ECHR):
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.
Hospital nurse Shirley Chaplin, from Exeter, who was denied from wearing a cross visibly around her neck, has lost her case for religious discrimination at the European Court of Human Rights.
She was told not to wear a cross due to health and safety in the hospital.
The European Court of Human Rights has found British Airways check-in clerk Nadia Eweida did face religious discrimination for not being able to wear a cross at work.
The other three Christians taking their case to Strasbourg have lost.
The court found for Ms Eweida's right to wear a cross over BA's wish to protect their corporate image. She has been awarded €2,000 (£1,660) and €30,000 (£34,910) in costs from the UK government.
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."
Judges at the European Court of Human Rights will rule today on a landmark case brought by four British Christians.
They claim they have suffered discrimination at work because of their faith.
- The four argue the actions of their employers contravened articles nine and 14 of the European Convention on Human Rights, which prohibit religious discrimination and allow "freedom of thought, conscience and religion"
- Government lawyers argue their rights are only protected in private
- Sixty-year-old British Airways employee Nadia Eweida, from London, says she was prevented from wearing a visible cross necklace
- Hospital nurse Shirley Chaplin, 57, from Exeter, who also feels she was prevented from wearing a cross visibly around her neck
- Gary McFarlane, 51, a Bristol marriage counsellor, who claims he was sacked for saying that he might not be comfortable in giving sex therapy to homosexual couples
- Registrar Lillian Ladele, from London, who said she was disciplined by London's Islington Council for refusing to conduct civil partnership ceremonies for homosexual couples