Abstract: A locking apparatus which is suitable for use with a manually operated control. The control is of a type which has a body and a handle. The handle is rotatable relative to the body and which is restricted to rotate between a first position defined by a first pair of abutment surfaces touching one another. In such a condition, a second pair of abutment surfaces are spaced apart to define a first gap between them. Rotation to a second limiting position is defined by the second pair of abutment surfaces touching one another and the first pair of abutment surfaces being spaced apart to define a second gap. The locking apparatus includes a first member which is attachable to the handle and a second member which is attached to the first member. The second member fits for use into either one of the first or second gap and provides further abutment surfaces each disposed to abut a respective adjacent abutment surface on the body of the control thereby to restrict rotation of the handle relative to the body.