Packet for smoking articles and relative cardboard blank

A packet for smoking articles, comprising an external casing, including a containing body and a lid rotatable around a hinge made on a wall of said external casing, and an internal casing slidable with respect to said external casing, said external casing comprising a further wall joined to said internal casing and detachable from said external casing so as to be distanced from said containing body when said internal casing is at least partially extracted from said external casing, said external casing further comprising lateral walls being provided on opposite sides of said further wall and connected to corresponding further lateral walls of said internal casing, said lateral walls being distanced from said containing body and said lateral walls remaining integral with said internal casing when said internal casing is at least partially extracted from said external casing, and

• one of an intended breakage line interposed between said further wall and said containing body, said intended breakage line being able to be broken to separate said further wall from said containing body, and a cutting line interposed between said further wall and said containing body, said cutting line being able to be cut to separate said further wall from said containing body,
• wherein an internal surface of each of said lateral walls includes a gluing point to adhere each of said lateral walls to the corresponding further lateral wall of said internal casing so as to keep said internal casing closed around an internal wrapping comprising a composition of smoking articles, and so as to attach said further wall to said internal casing.