A support structure (10) for supporting a plurality of utility modules (11) in an array, said structure comprising two elongate support elements (16) and holding means (13) for holding the said two elongate support elements (16) in a predetermined juxtaposed relationship with respective opposite longitudinal edges thereof parallel to one another and in pairs comprising one from each of said elongate support elements (16), in which the said utility modules (11) are locatable between each said pair of longitudinal edges, and in which the said holding means (13) span between the said elongate support elements (16) at intervals along the length of the said elongate support elements (16) such that the said utility modules (11) may be located between the two edges of a said pair at selected positions along the length of the said elongate elements (16) and may extend beyond the median plane between the said elongate support elements (16).