A lift for telescopic passenger stairs enabling passengers with reduced mobility to board a plane, wherein said lift comprises: - a folding platform onto which a wheelchair can be wheeled; - the platform being attached to a guide rail with its back part using at least three guide wheels for moving the platform along the guide rail ; characterized in that - the guide rail is shaped as a long element of an essentially rectangular shape with a cross-section in the shape of a letter C and with a shorter part on one end ; and the lift further comprises: - an endless chain or a wire rope , running within the guide rail on at least one sprocket and at least three guide rollers , which can also be sprockets, wherein said endless chain or wire rope is driven via a drive through a self-locking gear drive for stopping the platform at any point; - the said guide rail having a lock for locking the platform in place, when it reaches the top of the guide rail ; and wherein the guide rail is arranged to be built into one of the sides of telescopic passenger stairs, and wherein the endless chain or wire rope within the guide rail enables the platform to move along the guide rail when the platform is in the area of a lower staircase of telescopic stairs, and movement of the guide rail along an upper staircase of telescopic stairs when the platform is at the uppermost point of the guide rail , so that the chain pulls the guide rail upwards with the platform . - a folding platform onto which a wheelchair can be wheeled; - the platform being attached to a guide rail with its back part using at least three guide wheels for moving the platform along the guide rail ; characterized in that - the guide rail is shaped as a long element of an essentially rectangular shape with a cross-section in the shape of a letter C and with a shorter part on one end ; and the lift further comprises: - an endless chain or a wire rope , running within the guide rail on at least one sprocket and at least three guide rollers , which can also be sprockets, wherein said endless chain or wire rope is driven via a drive through a self-locking gear drive for stopping the platform at any point; - the said guide rail having a lock for locking the platform in place, when it reaches the top of the guide rail ; and wherein the guide rail is arranged to be built into one of the sides of telescopic passenger stairs, and wherein the endless chain or wire rope within the guide rail enables the platform to move along the guide rail when the platform is in the area of a lower staircase of telescopic stairs, and movement of the guide rail along an upper staircase of telescopic stairs when the platform is at the uppermost point of the guide rail , so that the chain pulls the guide rail upwards with the platform . - an endless chain or a wire rope , running within the guide rail on at least one sprocket and at least three guide rollers , which can also be sprockets, wherein said endless chain or wire rope is driven via a drive through a self-locking gear drive for stopping the platform at any point; - the said guide rail having a lock for locking the platform in place, when it reaches the top of the guide rail ; and <EOS>