Leuco polymers as bluing agents in laundry care compositions

A leuco polymer comprising a polymeric carbohydrate and a leuco moiety, wherein the polymeric carbohydrate and the leuco moiety are covalently bound, the leuco moiety has a maximum molar extinction coefficient at a wavelength in the range of 400 nm to 750 nm of less than 1000 M−1 cm−1, the polymeric carbohydrate is a substituted polysaccharide in which at least a portion of hydroxy groups of the polysaccharide are replaced with a group of the formula —O—R or —O—C(═O)—R, where R is selected from the group consisting of hydroxyalkyl, carboxyalkyl and salts thereof, and sulfoalkyl and salts thereof, where the substituted polysaccharide has a degree of substitution of from 0.50 to 0.95, and wherein the leuco moiety is selected from the group consisting of diarylmethane leuco moieties, oxazine moieties, thiazine moieties, hydroquinone moieties, and arylaminophenol moieties.