a support structure for a rostrum includes a first a - frame ; and at least a second a - frame , nestable and retractable into the first a - frame . the support structure may have an open central area and the second a - frame may be substantially the same as , but smaller than , the open central area of the first a - frame . at least one support means is connected to each a - frame for supporting a load , wherein the support is connected to an upper portion of one a - frame . the support extends from the upper portion of the one a - frame and is co - operable with an upper portion of another a - frame . the support structure may be telescopic and configured to be expandable and retractable between a retracted , stored position , and an extended , in use position .