UK's Equality Act

https://www.washingtonpost.com/news/voraciously/wp/2020/01/03/ethical-veganism-is-a-protected-class-akin-to-religion-in-the-u-k-after-a-landmark-ruling/

As per UK's Equality law, the belief must 

 be “genuinely held; be a belief and not an opinion or viewpoint based on the present state of information available; 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; and be worthy of respect in a democratic society, compatible with human dignity and not conflict with the fundamental rights of others