A fan assembly for a gas turbine, the assembly comprising: a fan surrounded by a fan casing; a resilient, radially flexible containment material wrapped around the outside of the fan casing for containing a fan blade which has breached the casing during a fan blade-off event, and characterized in that the fan assembly comprises: a retaining cable arrangement for resisting separation of a first portion of the casing from a second portion of the casing as a result of said breach occurring between the first and second portion, wherein the cable arrangement comprises: a retaining cable on the outside of the containment material, secured between the first and second portion (10, 12) of the casing, the retaining cable being sufficiently radially compliant for radial deflection to accommodate radial flexing of the containment material caused by impact of said fan blade inbetween the first and second portion (10, 12); and a locking arrangement operable to subsequently lock the retaining cable between the first and second portions of the casing whereby separation of the first and second portions is resisted by tension in the locked cable. a fan surrounded by a fan casing; a resilient, radially flexible containment material wrapped around the outside of the fan casing for containing a fan blade which has breached the casing during a fan blade-off event, and characterized in that the fan assembly comprises: a retaining cable arrangement for resisting separation of a first portion of the casing from a second portion of the casing as a result of said breach occurring between the first and second portion, wherein the cable arrangement comprises: a retaining cable on the outside of the containment material, secured between the first and second portion (10, 12) of the casing, the retaining cable being sufficiently radially compliant for radial deflection to accommodate radial flexing of the containment material caused by impact of said fan blade inbetween the first and second portion (10, 12); and a locking arrangement operable to subsequently lock the retaining cable between the first and second portions of the casing whereby separation of the first and second portions is resisted by tension in the locked cable. a retaining cable arrangement for resisting separation of a first portion of the casing from a second portion of the casing as a result of said breach occurring between the first and second portion, wherein the cable arrangement comprises: a retaining cable on the outside of the containment material, secured between the first and second portion (10, 12) of the casing, the retaining cable being sufficiently radially compliant for radial deflection to accommodate radial flexing of the containment material caused by impact of said fan blade inbetween the first and second portion (10, 12); and a locking arrangement operable to subsequently lock the retaining cable between the first and second portions of the casing whereby separation of the first and second portions is resisted by tension in the locked cable. a retaining cable on the outside of the containment material, secured between the first and second portion (10, 12) of the casing, the retaining cable being sufficiently radially compliant for radial deflection to accommodate radial flexing of the containment material caused by impact of said fan blade inbetween the first and second portion (10, 12); and a locking arrangement operable to subsequently lock the retaining cable between the first and second portions of the casing whereby separation of the first and second portions is resisted by tension in the locked cable.