Views including pacifism and supporting Scottish independence are protected philosophical beliefs under the Act.

If he is successful, it will mean that bosses cannot discriminate against members of staff who identify as ethical vegans - meaning employees could refuse to wear certain uniforms depending on their material composition, or undertake certain duties linked to companies which support animal testing.

Mr Casamitjana, who grew up in Barcelona, Spain, moved to London in 2005 and became an ethical vegan in 2001.

He practices ethical veganism so strictly that he does not allow anyone to bring non-vegan food into his home, nor does he travel short distances on public transport to avoid “accidental crashes with insects or birds that may occur when taking the bus”.

He also refuses to sit on leather seats, romantically date anyone who is not a vegan or eat figs because the “symbiotic relationship” the fruit has with wasps.

“You can therefore not be sure whether any of the wasps’ larvae is still inside the ripened fig and therefore I consider consumption of figs to be inconsistent with veganism,” he wrote in his witness statement to the court.

“Ethical veganism is now my creed and the ethical imperative in my life,” Mr Casamitjana said. “The way I treat my belief in ethical veganism is no different to the way those who practice a religion treat the rules which govern their religion.

“I believe that the arguments for veganism are so self-evidently correct and universally beneficial that eventually animal exploitation will be seen as so undesirable as to effectively bring in it to an end, in much the same way that human slavery was eventually recognised as morally wrong after centuries of broad social acceptance.”