A fully mounted plough (20) having a plough frame (21), coupling means (30), a number of plough bodies (22) and a lateral adjustment mechanism (2, 3, 4), in which: the plough frame (21) includes a plough beam (6) having supports (8) each mounting a respective plough body (22), a control rod (7) extends alongside the plough beam (6), the adjustment mechanism includes a control arm (4), the interconnecting pivots (23, 24, 25, 26) are located each at a respective corner of a parallelogram type linkage, the coupling means (30) includes a mounting bracket (1) to which the control arm (4) is connected via a pair of parallel links (2, 3) so that the links (2, 3) function as a parallelogram linkage to move the plough beam (6) and the control rod (7) laterally; and an actuator (5) is coupled with the mounting bracket (1) and which is operative to adjust the frame (21) laterally.