Many have been there for a long time and so there are a few cliques that can potentially make the atmosphere a little less welcoming (although I suppose this could be an issue in any office. I have just never experienced it to this scale at any of the numerous offices I have worked in before, or since). The firm, at the time, needed a better diversity and inclusion policy, as it appeared a lot of people who were "different" (race, or had an accent etc), felt a bit more out of place - a fact openly stated by several people I was working with at the time. To be fair to them, they did have a number of mandatory inclusivity training sessions and it is clear that some effort and thought is being made however it just was not translating well- at least at the time.