An extendable/retractable ladder, comprising: a first stile comprising a plurality of columns (108, 110, 122, 124, 126) disposed in a nested arrangement for relative axial movement in a telescopic fashion along an axis of the plurality of columns (108, 110, 122, 124, 126), the plurality of columns (108, 110, 122, 124, 126) including first and second adjacent columns (122, 124), the second column nesting in the first column; a second stile; a plurality of rungs (118, 120, 134, 146, 152) extending between the first stile and the second stile; a connector assembly coupled to a first column in the plurality of columns (108, 110, 122, 124, 126) proximate an end thereof and coupled to a rung of the plurality of rungs (118, 120, 134, 146, 152), the connector assembly having a rung portion, the rung portion inserted into a first end of the rung; and a locking pin assembly forming part of the connector assembly for selectively locking relative axial movement between the first column and the second column, the locking pin assembly including a release button, a central post extendable into apertures in the first and second columns (122, 124) to lock relative axial movement therebetween, the central post being retractable from at least the aperture in the second column via the release button to permit relative axial movement between the first column and second column, and the rung including a relief slot that extends centrally from the first end of the rung, the relief slot permitting actuation of the release button and insertion of the locking pin assembly into the first end of the rung characterised in that the release button is formed integrally with the central post. a first stile comprising a plurality of columns (108, 110, 122, 124, 126) disposed in a nested arrangement for relative axial movement in a telescopic fashion along an axis of the plurality of columns (108, 110, 122, 124, 126), the plurality of columns (108, 110, 122, 124, 126) including first and second adjacent columns (122, 124), the second column nesting in the first column; a second stile; a plurality of rungs (118, 120, 134, 146, 152) extending between the first stile and the second stile; a connector assembly coupled to a first column in the plurality of columns (108, 110, 122, 124, 126) proximate an end thereof and coupled to a rung of the plurality of rungs (118, 120, 134, 146, 152), the connector assembly having a rung portion, the rung portion inserted into a first end of the rung; and a locking pin assembly forming part of the connector assembly for selectively locking relative axial movement between the first column and the second column, the locking pin assembly including a release button, a central post extendable into apertures in the first and second columns (122, 124) to lock relative axial movement therebetween, the central post being retractable from at least the aperture in the second column via the release button to permit relative axial movement between the first column and second column, and the rung including a relief slot that extends centrally from the first end of the rung, the relief slot permitting actuation of the release button and insertion of the locking pin assembly into the first end of the rung characterised in that the release button is formed integrally with the central post.