Smoking article and mouthpiece therefor

A mouthpiece attachable to a rod portion of a smoking article, the mouthpiece comprising an elongate cylindrical element formed from plastic as a hollow tube arranged to be inserted into a corresponding recess of the smoking article rod portion by a user;

• wherein the cylindrical element comprises an outer surface having at least one circumferentially extending raised area, and the at least one circumferentially extending raised area is configured to engage with an inner surface of the recess to prevent or restrict air flow between the inner surface of the recess and an outer surface of the mouthpiece, so as to prevent or restrict the ingress of external air into the smoking article between the smoking article rod portion and the mouthpiece,
• wherein the at least one circumferentially extending raised area forms a continuous band or ring around the cylindrical element, and
• wherein the cylindrical element comprises a smoke modifying additive, and adjacent first and second portions each extending partially along the length of the cylindrical element, the first portion being arranged to be inserted into the recess by a user;
• and
• the mouthpiece having a larger external diameter at the second portion than the internal diameter of the recess, and an end surface of the second portion being configured to abut an end surface of the rod portion to prevent further insertion of the mouthpiece.