Must you show disadvantage to a particular group of workers apart from just you?

Usually, but not always. In Eweida and Others v The United Kingdom [2013] IRLR 231, a claim for religious discrimination taken to the European Court of Human Rights (ECHR), the ECHR ruled that a British Airways check-in operative who was not allowed to wear a visible crucifix at work (see page 163), could bring her claim for indirect religious discrimination even though she was the only BA employee affected.