The evaporative and tidal disruption of proto-giobular clusters has been analysed taking into account the influence of galactocentric distances. We confirm that current theories agree with the survival of present globular clusters, although they do not explain the observed lack of massive bright clusters more distant than 13 kpc. For these remote clusters we find evidence for surface brightness decreasing with the cluster metallicity, at variance with the inner halo clusters. If such a behaviour is taken into account, the whole globular clusters' system appears fully compatible with the theoretical predictions about disruption. We suggest that present distant clusters might represent the survival of the first extremely metal-poor (Population III?) galactic substructures.