High lift system for an aircraft, comprising a wing structure and a leading edge slat movably supported relative to a leading edge of the wing structure, the leading edge slat comprising a) a leading edge and a trailing edge, wherein the trailing edge is configured to take different positions to form a gap between the leading edge slat and the wing structure, b) a skin enclosing an interior space of the leading edge slat, the skin having a flexible leading skin section facing away from the wing structure, and a flexible trailing skin section facing towards the wing structure, c) at least one actuation arrangement (20, 21, 41, 61, 61, 62, 63, 66, 67, 69, 71) arranged inside the interior space, configured for selectively introducing a normal force onto both of the leading skin section and the trailing skin section at the same time, such that their distance is decreased upon introducing the normal force, d) wherein said normal force changes the profile of the skin in such a way that the trailing edge changes its position relative to the wing structure to selectively close or open the gap between the leading edge slat and the wing structure; e) wherein the at least one actuation arrangement (20, 21, 41, 61, 61, 62, 63, 66, 67, 69, 71) comprises a rotary actuator, which is coupled with at least one lever (24, 60), pivotably attached to a joint on the inside of at least one of the trailing skin section and the leading skin section; and f) wherein the rotary actuator comprises a pair of bevel gears (52, 54), couplable with a spindle screw (56, 64), which engages with a screw nut couplable with at least one of the trailing skin section and the leading skin section of the slat by means of at least one coupling element. a) a leading edge and a trailing edge, wherein the trailing edge is configured to take different positions to form a gap between the leading edge slat and the wing structure, b) a skin enclosing an interior space of the leading edge slat, the skin having a flexible leading skin section facing away from the wing structure, and a flexible trailing skin section facing towards the wing structure, c) at least one actuation arrangement (20, 21, 41, 61, 61, 62, 63, 66, 67, 69, 71) arranged inside the interior space, configured for selectively introducing a normal force onto both of the leading skin section and the trailing skin section at the same time, such that their distance is decreased upon introducing the normal force, d) wherein said normal force changes the profile of the skin in such a way that the trailing edge changes its position relative to the wing structure to selectively close or open the gap between the leading edge slat and the wing structure; e) wherein the at least one actuation arrangement (20, 21, 41, 61, 61, 62, 63, 66, 67, 69, 71) comprises a rotary actuator, which is coupled with at least one lever (24, 60), pivotably attached to a joint on the inside of at least one of the trailing skin section and the leading skin section; and f) wherein the rotary actuator comprises a pair of bevel gears (52, 54), couplable with a spindle screw (56, 64), which engages with a screw nut couplable with at least one of the trailing skin section and the leading skin section of the slat by means of at least one coupling element.