A method of making a diluted organopolysiloxane containing polymer comprising the steps of:-- (i) Preparing an organopolysiloxane containing polymer by reacting a siloxane containing material with:-- (a) one or more organopolysiloxane polymers(s) or (b) one or more organic polymers(s) via an addition reaction pathway in the presence of an extender and/or plasticiser, a suitable catalyst and optionally an end-blocking agent; and (iii) Where required quenching the polymerisation process;wherein the extender and/or plasticiser is substantially retained within the resulting diluted organopolysiloxane containing polymer.