A steering column assembly has a clamp securing a shroud 2 to a bracket 4 fixed to a vehicle. The clamp comprises a locking lever 8 and a clamp pin 5 having a cam mechanism. The cam mechanism comprises first and second cam portions relatively moveable by operating lever 8, varying the length of the cam mechanism and applying a variable clamping force to shroud 2. The clamp mechanism also includes a friction brake acting on pin 5, preferably a coiled spring (20, Figure 2) mounted on pin 5, applying an increasing amount of braking force opposing movement of lever 8 during unlocking; suitably, this may prevent rapid movement of lever 8 during movement over centre. The spring may have legs 21, 22 fixed respectively to lever 8 and to shroud 2, bracket 4 or pin 5; typically, legs 21, 22 move angularly relative to each other during clamping and unclamping.
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