A collapsible steering column assembly for a vehicle comprises a shroud (1, 2)which surrounds a steering column shaft, a mounting bracket secured to or integral with a fixed part of the vehicle, a support bracket (3) secured to the mounting bracket through one or more frangible connectors (5), a clamp mechanism (9) which releasably secures the shroud (1, 2) to the support bracket (3), and a blocking part (14) which is fixed in position relative to the mounting bracket and at least in an undamped condition of the clamp mechanism (9) provides an additional force path between the clamp mechanism (9) and the mounting bracket that does not pass through the support bracket (3). In the event that an axial load is applied to the steering assembly when the clamp mechanism (9) is unlocked and has reached the end of its allowable travel at least some of the load is carried through the clamp mechanism (9) and the blocking part (14) to the mounting bracket along the additional force path.