Blue Single Breasted Waistcoat. Looking to step into spring 2024 in style? Check out this ladies blue single breasted waistcoat which is a new arrival at M&S. This cotton-rich denim waistcoat is a versatile layering piece for your smart wardrobe. It’s made in an easy relaxed fit and features a timeless single-breasted front with four-button fastening. A deep v-neckline adds a feminine touch. This piece is lined for comfort. M&S Collection: easy-to-wear wardrobe staples that combine classic and contemporary styles