The latest ruling from the European Court of Human Rights makes a crucial and interesting distinction. http://www.bbc.co.uk/news/uk-21025332
Employees have the right to wear religious symbols at work and hence the BA Employee did have the right to wear her Christian Cross visibly.
What employees (Christian or otherwise) do not have the right to do is to discriminate in the course of their work, even for religious reasons. That will be disappointing to some Christian groups but seems to make sense. If you were a pacifist why would you apply for a job in the Army? And, if you did, you could hardly object when asked to fire a gun. Individuals need to choose work that does not compromise their values.
There must be sympathy for the marriage guidance counsellor who does not want to counsel homosexuals or the registrar who does not want to conduct Civil Ceremonies. The law has changed (as have society’s values) since they took up their career. In both cases you might expect a good employer would find them alternative work.
More difficult is a situation where the whole company’s values change and there is no alternative employment. This happened to those who worked for Alpro with its humane farming methods only to find the company taken over by a US factory farming company. When the company’s values change, there is little remedy for the employees.
But that is the price of enabling employers to be able to expect employees to carry out the work for which they were employed. They are not obliged to accept refusal on the grounds of religion or belief. What employers cannot now do is to insist employees leave religious symbols at home.