Nadia Eweida, a devout Christian, was sent home in September 2006 after refusing to conceal the symbol, which she claimed was an expression of her faith.
She claimed she was entitled to £12,000 compensation in damages and to cover lost salary before her eventual return to work after BA relaxed their uniform rules the following year.
But the High Court decided BA was justified in applying a blanket ban on the wearing of visible jewellery for a customer-facing employee. The court ruled Eweida was not indirectly discriminated against because the company made it clear such jewellery should not be visible.
Emma Clark, employment specialist at Fox, said: "This decision is a sensible interpretation of the nuances of the indirect discrimination legislation; Miss Eweida's desire to display a cross around her neck in the workplace was a personal choice and not a religious requirement."
Philip Henson, partner and employment specialist at law firm Bargate Murray, said: "Even though Eweida's case of indirect discrimination had been defeated by BA's position of justification it is unlikely that this will be the end of the matter. Ms Eweida has become a cause célèbre in various circles; she has the backing of cross-party politicians, and the Church, who seem to view her case as one of freedom of religious expression. Due to the political and religious maelstrom it is widely predicted that Ms Eweida and her legal team may soon be knocking on the rather ornate door of the Supreme Court.
"This case does not appear to be about money. In an earlier decision in the Court of Appeal in October last year (concerning a Protective Costs Order) it was recorded that in October 2007 BA made an open offer to Ms Eweida to pay her £8,500 and to pay £50,000 to UNICEF in order to settle the claim, which she rejected."