Flame retardant optical cable

A flame-retardant optical cable (10) is disclosed which comprises a polymeric central loose tube (3) housing optical fibres (1), a metallic armour (6) surrounding the polymeric central loose tube (3) and a multi- layered sheath (7) surrounding and in direct contact with the metallic armour (6), wherein the multi-layered sheath (7) comprises an inner layer (7a), an intermediate layer (7b) and an outer layer (7c), all made of a LS0H flame-retardant material, the LS0H material of the intermediate layer (7b) having a limiting oxygen index (LOI) higher than the LOI of the LS0H material of the inner layer (7a) and of the outer layer (7c). Such cable has improved flame-retardant properties, particularly in terms of slowing flame propagation, heat release, droplets and emission of smokes, when it is exposed to flames during fire.