Get summer ready with this black floral strapless maxi dress from the M & S collection. Elasticated bust with ties at the top for perfect fit and halterneck ties at the neck , size 18 length from underarm 50" elasticated bust unstretched 19" stretches up to 23"-24" across,so would probably also fit 18/20? But please check measurements, flattering fit, worn quite a bit but still plenty of wear to be had. Thanks for looking!