A legal hearing which starts in Norwich today will determine whether veganism is a 'philosophical or religious belief' - and therefore whether it is protected in law.
The case follows the firing of an employee by advocacy organization The League Against Cruel Sports (LACS).
According to Jordi Casamitjana, LACS sacked him after he raised concerns that its pension fund was being invested in companies involved in animal testing.
He claims he was 'unfairly disciplined' for making this disclosure, and that he was fired because of his philosophical belief in ethical veganism.
According to Casamitjana's lawyers, ethical veganism satisfies the tests required for it to be a philosophical or religious belief, which means it should protected under the Equality Act 2010.
To qualify as a protected belief under the Act, a belief must meet a set of criteria. It must be genuinely held, be a belief as to a weighty and substantial aspect of human life and behavior, attain a certain level of cogency, seriousness, cohesion and importance.
It must also be worthy of respect in a democratic society, not be incompatible with human dignity and not conflict with the fundamental rights of others, and be a belief, not an opinion or viewpoint based on the present state of information available.
'Protection from discrimination'
"Ethical veganism is a philosophical belief held by a significant portion of the population in the UK and around the world," Peter Daly, a solicitor with Slater and Gordon who is acting for Casamitjana, said in a statement.
"This case, if successful, will establish that the belief entitles ethical vegans to protection from discrimination.
"The case we have prepared sets out how the belief in principle, and how Jordi's particular interpretations of it, meet the required legal test."
When he initially brought the case, Casamitjana said it was not primarily about his dismissal but about establishing ethical veganism as a philosophical belief.
"Although the manner in which I was dismissed was intensely distressing for me, some good may come of it if I am able to establish this valuable protection for all ethical vegans," he said.
"If we are successful in that hearing, we will then proceed to a hearing on the specifics of my dismissal."
'Inappropriate to comment further'
The League Against Cruel Sports says it sacked Casamitjana for gross misconduct.
"The League Against Cruel Sports is an inclusive employer, and as this is a hearing to decide whether veganism should be a protected status, something which the league does not contest, it would be inappropriate for us to comment further," it said in a statement to the BBC.