A reach adjustable steering column assembly comprising: a telescopic steering shaft which in use supports a steering wheel of the vehicle; a shroud that supports the steering shaft comprising an upper shroud part and a lower shroud part, the upper shroud part moving telescopically relative to the lower shroud part during reach adjustment of the steering column assembly, a support bracket that supports the shroud relative to a vehicle body, and a clamp mechanism that is operable between an unclamped position in which the steering column assembly is adjustable for reach and a clamped position in which the reach position of the steering column assembly is fixed, in which the clamp mechanism comprises a first locking part that is displaceable by an actuator assembly into and out of positive engagement with a second locking part, the first and second locking parts (122,136) being engaged in the clamped position and disengaged in the unclamped condition, the first locking part being fixed to one of the lower shroud part and the support bracket, and the second locking part during normal use being fixed to the upper shroud part so that it moves with the upper shroud part during reach adjustment but during a crash the second locking part being free to move relative to the upper shroud part, an energy absorbing mechanism that acts between the upper shroud part and the second locking part and is configured so that during a crash whereby the upper shroud part moves telescopically relative to the lower shroud part with the clamp assembly in the clamped position a deformable part of the energy absorbing mechanism is plastically deformed by a deforming part, thereby controlling the movement of the upper shroud part, and in that one of the deformable part and the deforming part of the energy absorbing mechanism is secured to the upper shroud part, and the other is fixed relative to the second locking part, and wherein the actuator assembly comprises a bolt that passes across an upper face of the shroud, the bolt being connected to the first locking part through a mechanism that converts rotary movement of the bolt into reciprocal movement of the first locking part, and characterized by further comprising an anti-abuse mechanism for preventing engagement of the energy absorbing mechanism when the clamping mechanism is in an unclamped position wherein the anti-abuse mechanism comprises a rocker arm that pivots around a pivot point having a first arm that extends in one direction from the pivot point and engages the first locking part and a locking finger that extends in another direction away from the pivot point and moves up and down in opposition to the movement of the first locking part such that when the first locking part is raised the finger is lowered and when the first locking part is lowered the finger is lifted. a telescopic steering shaft which in use supports a steering wheel of the vehicle; a shroud that supports the steering shaft comprising an upper shroud part and a lower shroud part, the upper shroud part moving telescopically relative to the lower shroud part during reach adjustment of the steering column assembly, a support bracket that supports the shroud relative to a vehicle body, and a clamp mechanism that is operable between an unclamped position in which the steering column assembly is adjustable for reach and a clamped position in which the reach position of the steering column assembly is fixed, in which the clamp mechanism comprises a first locking part that is displaceable by an actuator assembly into and out of positive engagement with a second locking part, the first and second locking parts (122,136) being engaged in the clamped position and disengaged in the unclamped condition, the first locking part being fixed to one of the lower shroud part and the support bracket, and the second locking part during normal use being fixed to the upper shroud part so that it moves with the upper shroud part during reach adjustment but during a crash the second locking part being free to move relative to the upper shroud part, an energy absorbing mechanism that acts between the upper shroud part and the second locking part and is configured so that during a crash whereby the upper shroud part moves telescopically relative to the lower shroud part with the clamp assembly in the clamped position a deformable part of the energy absorbing mechanism is plastically deformed by a deforming part, thereby controlling the movement of the upper shroud part, and in that one of the deformable part and the deforming part of the energy absorbing mechanism is secured to the upper shroud part, and the other is fixed relative to the second locking part, and wherein the actuator assembly comprises a bolt that passes across an upper face of the shroud, the bolt being connected to the first locking part through a mechanism that converts rotary movement of the bolt into reciprocal movement of the first locking part, and characterized by further comprising an anti-abuse mechanism for preventing engagement of the energy absorbing mechanism when the clamping mechanism is in an unclamped position wherein the anti-abuse mechanism comprises a rocker arm that pivots around a pivot point having a first arm that extends in one direction from the pivot point and engages the first locking part and a locking finger that extends in another direction away from the pivot point and moves up and down in opposition to the movement of the first locking part such that when the first locking part is raised the finger is lowered and when the first locking part is lowered the finger is lifted.