A single pack heat curable polyurethane composition comprises an isocyanate-terminated prepolymer liquid phase and a separate solid polyhydroxyl compound phase insoluble in the prepolymer phase, and is suitable for use as an adhesive. The liquid prepolymer phase comprises the reaction product of an aromatic polyisocyanate and a polyhydroxyl compound. The separate insoluble solid polyhydroxyl compound phase is dispersed or suspended throughout the liquid prepolymer phase and remains separate until heat cured. The ratio of OH groups in the solid polyhydroxyl compound phase to NCO groups in the isocyanate-terminated prepolymer liquid phase is less than 2:1. The single pack polyurethane adhesive composition can also be used as an in-mould coating and an injection moulding composition.