This is a white Ben Zuckerman 3 piece ensemble, very similar to the one below, but without the fur trim.
Ben Zuckerman was well known for having a very large collection each season, often over 300 outfits, but often the outfits were variations on a theme- different material, trimming or colours, but very similar otherwise. I have this same suit in a tan colour with a slightly different material.
Photos courtesy of  Augusta Auctions.