A Westcountry nurse who was banned from wearing a visible crucifix at work will fight her case in the European Court of Human Rights today.
Shirley Chaplin was relegated to paperwork duties at the Royal Devon and Exeter Hospital after 31 years of nursing, because she refused to stop wearing a necklace bearing a cross.
She lost a tribunal in 2010, but tomorrow she is one of four cases to be heard which lawyers have said are "pivotal" to protecting the freedom of Christians in the workplace.
Paul Coleman, of Alliance Defending Freedom, which unites lawyers with Christian organisations to defend rights within the faith, will be fighting the case in Strasbourg, France, alongside lead counsel Paul Diamond.
Mr Coleman said: "Christian employees should not be singled out for discrimination.
"No one should have to hide their faith or act contrary to it. This type of intolerance is inconsistent with the values of civilised communities."
Mrs Chaplin, 56, took early retirement after she was told her crucifix breached health and safety guidelines. She said she was "distraught and upset", and felt as if her faith was being questioned.
The hospital insisted it had acted in an appropriate and sensitive matter, and said she had been given alternative ways to wear the cross, but chose not to accept them.
In 2010, an Employment Appeal Tribunal ruled against her claim because it said Christians "generally" did not consider wearing a cross as a requirement of their religion.
The case has sparked a heated debate on all sides, with comment from secularists, bishops and the Prime Minister.
The National Secular Society said it agreed with the hospital's decision.
But in July, David Cameron said he fully supported the right of people to wear religious symbols at work. He said: "I think it is an absolutely vital freedom."
The nurse's case has been consolidated with that of Nadie Eweida, a British Airways check-in counter worker at Heathrow Airport who was asked to cover up her crucifix.
The other two cases, also grouped together as one, involve Lillian Ladele, a marriage registrar for Islington Council in London, who was disciplined after she asked to be exempt from registering same-sex civil partnerships. Alongside her is Gary McFarlane, a counsellor who was fired after he declined to unequivocally commit to provide same-sex couples with psycho-sexual therapy.
The cases represent the latest step in a series of fights by Christians who feel their right to express their religion is under fire.
At Easter, Local Government Minister Eric Pickles intervened to effectively overturn a High Court decision that it was illegal for councils to hold prayers before meetings, sparked by a challenge by Bideford Town Councillor Clive Bone, supported by the National Secular Society.
Mr Pickles evoked the Localism Act to speed up the process and ensure that councils made their own decision on the matter.