A method of forming a post-tensioned concrete member comprising: positioning a post-tensioning tendon within a concrete form, the post-tensioning tendon including a tension member, fixed anchor, and a stressing end anchor; positioning a pocket former (100, 200, 300, 400, 500) between the stressing end anchor and the concrete form, the pocket former (100, 200, 300, 400, 500) including: a pocket former body (101, 201, 301, 401, 501), the pocket former body (101, 201, 301, 401, 501) having an outer surface, the pocket former body (101, 201, 301, 401, 501) having a tension member channel therethrough; and a collapsible element (103, 203, 303, 403, 503), the collapsible element (103, 203, 303, 403, 503) formed on the outer surface of the pocket former body (101, 201, 301, 401, 501), the collapsible element (103, 203, 303, 403, 503) extending radially outwardly from the pocket former body (101, 201, 301, 401, 501); inserting the tension member through the tension member channel of the pocket former body (101, 201, 301, 401, 501); placing concrete into the concrete form such that the post-tensioning tendon and the pocket former are encased in the concrete; applying force to the pocket former body (101, 201, 301, 401, 501); collapsing the collapsible element (103, 203, 303, 403, 503) toward the pocket former body (101, 201, 301, 401, 501); and forming a cavity within the concrete by removing the pocket former body (101, 201, 301, 401, 501) from the concrete; optionally, further comprising after forming a cavity: applying tensile stress to the tension member; and filling the cavity with filling material, the method being characterised in that the pocket former further comprises pocket former bridges, and in that the method further comprises: applying force to the pocket former bridges; and separating the pocket former body into two or more segments. positioning a post-tensioning tendon within a concrete form, the post-tensioning tendon including a tension member, fixed anchor, and a stressing end anchor; positioning a pocket former (100, 200, 300, 400, 500) between the stressing end anchor and the concrete form, the pocket former (100, 200, 300, 400, 500) including: a pocket former body (101, 201, 301, 401, 501), the pocket former body (101, 201, 301, 401, 501) having an outer surface, the pocket former body (101, 201, 301, 401, 501) having a tension member channel therethrough; and a collapsible element (103, 203, 303, 403, 503), the collapsible element (103, 203, 303, 403, 503) formed on the outer surface of the pocket former body (101, 201, 301, 401, 501), the collapsible element (103, 203, 303, 403, 503) extending radially outwardly from the pocket former body (101, 201, 301, 401, 501); a pocket former body (101, 201, 301, 401, 501), the pocket former body (101, 201, 301, 401, 501) having an outer surface, the pocket former body (101, 201, 301, 401, 501) having a tension member channel therethrough; and a collapsible element (103, 203, 303, 403, 503), the collapsible element (103, 203, 303, 403, 503) formed on the outer surface of the pocket former body (101, 201, 301, 401, 501), the collapsible element (103, 203, 303, 403, 503) extending radially outwardly from the pocket former body (101, 201, 301, 401, 501); inserting the tension member through the tension member channel of the pocket former body (101, 201, 301, 401, 501); placing concrete into the concrete form such that the post-tensioning tendon and the pocket former are encased in the concrete; applying force to the pocket former body (101, 201, 301, 401, 501); collapsing the collapsible element (103, 203, 303, 403, 503) toward the pocket former body (101, 201, 301, 401, 501); and forming a cavity within the concrete by removing the pocket former body (101, 201, 301, 401, 501) from the concrete; optionally, further comprising after forming a cavity: applying tensile stress to the tension member; and filling the cavity with filling material, the method being characterised in that the pocket former further comprises pocket former bridges, and in that the method further comprises: applying tensile stress to the tension member; and filling the cavity with filling material, the method being characterised in that the pocket former further comprises pocket former bridges, and in that the method further comprises: applying force to the pocket former bridges; and separating the pocket former body into two or more segments.