The invention relates to a nacelle for a turbojet, of the type comprising a downstream structure having an outer structure (6) that defines, together with an inner concentric structure (9) for surrounding the downstream portion of the turbojet, an annular flow channel (8), characterised in that a portion at least of said inner structure (9) is mounted so as to be capable of a translation movement along the longitudinal axis of the nacelle so that it can move between a working position, in which the inner structure acts as a casing for the downstream portion of the turbojet, and a maintenance position in which the inner structure exposes said downstream portion of the turbojet.