This is a Ben Zuckerman suit, in a blue and black plaid. The suit is a thick, substantial wool and would have, in all likelihood, been made at a top fabric mill.
An interesting design feature on the jacket is the trim around the opening, neckline and bottom. The material at the edge is 'puffed' and really stands out from the main body of the suit. The buttons are black, and for Ben Zuckerman are relatively plain, which I believe indicates that this suit was strictly for daytime wear, as Zuckerman suits with jewelled or beaded buttons tend to be cocktail suits.
This suit was sold at Saks Fifth Avenue.
Photos courtesy of freckles07051b3a.