A steerable tube for endoscopic applications includes a set of longitudinal elements arranged for interconnecting a proximal and a distal end portion of the steerable tube. The set of longitudinal elements is arranged for transferring a movement of the proximal to the distal end portion. The tube further includes an actuator coupled to the set of longitudinal elements at the proximal end portion, for manipulating the set of longitudinal elements, a flexible body that is arranged between the proximal and distal end portions for accommodating the set of longitudinal elements, and a coupling arrangement for establishing an adjustable coupling between the actuator and at least one of the longitudinal elements, thereby allowing the longitudinal elements to assume different lengths between the proximal and distal end portions. An endoscopic instrument, an endoscope and an assembly including a steerable tube set forth are also described.