Abstract: A telescopic supporting post (10) comprises two mutually displaceable telescope members (11, 12), each comprising an inner tubular portion (15, 17) of small diameter and an outer tubular portion (16, 18) of large diameter. Said inner portions (15, 17) are provided with cooperating bearing surfaces (15a, 17a) by which the two telescope members (11, 12) are mounted for axial displacement relatively to each other. Said outer portions (16, 18) are provided with cooperating interengagement means (19, 21) for holding the two telescope members (11, 12) against mutual rotation. In order to avoid the need for a separate turntable when it is desired to permit rotary movement of a chair supported by the post (10), said interengagement means (19, 21) are arranged for releasable engagement with each other, whereby the two telescope members may be rotated relatively to each other, utilizing said bearing surfaces also as rotary bearing surfaces, when said interengagement means are out of engagement with each other.