Measurements of the thermal conductivity of a model system (squat aluminium cylinders suspended in an aqueous carbohydrate polymer gel) have been performed for a range of compositions up to the packing factor limit of the aluminium (approximately 0.6). Of a variety of models considered, the Cheng–Vachon model provided the most accurate predictions of thermal conductivity, and it was argued that this would also be the case for suspensions of most metals in polymer matrices. A modified form of the Cheng–Vachon model was used to obtain an even closer fit to the experimental data.