Abstract: A leg extension device for use in levelling a ladder or other work platform requiring a level step, includes a first leg member and a second extending leg member, substantially parallel with, and in slidable relation, thereto. A belt, strap or cable cooperates between the first and second leg members to produce an extendable leg, which can be secured, or fastened, over a range of extended lengths by a clamping arrangement, which is operable on the belt, strap or cable. The clamping arrangement is activated to secure the strap in order to fix the length of the extendable leg, or is released, as required, to allow for a positive adjustment by way of either extension or contraction of the extending leg member to accommodate variations in the terrain on which the ladder is used.