The High-Cast Brahmin Surname

In the 70s growing up I was Banerjee in a very sort of overwhelmingly English working class area in West London and it was a foreign name. As soon as I went back to India to West Bengal where my family are from it's a different name. It's a name of the elite and of the privileged not elite in terms of money but it's a high-cast Brahmin surname. So you say a bit more about that? What does it mean to be high-cast to be Brahmin in the Indian context when you went back?