clustering properties. The strong clustering measured in the counts–in–cells analysis of Adelberger et al. (1998) and in the correlation–function analysis of Giavalisco & Dickinson (2001), and the dependence of the correlation length on luminosity detected in the latter study, were interpreted as implying that LBGs are associated with dark matter haloes of high mass – consistent with a simple model in which LBGs pinpoint all the highest mass dark matter haloes at that epoch. We refer to this model as the ‘massive–halo’ model and use the results of the analysis by Mo, Mao & White (1999; hereafter MMW) as defining the model. Their figure 4 provides the predicted distribution of halo circular velocities at the virial radius, and yields a median halo virial mass of $10^{12.3}$[${\mathrm M_{\odot}\thinspace}$]{}for the LBG population. The massive–halo model leaves no room for other high–redshift populations, that do not meet the LBG criteria, to occupy the high–mass tail of the halo distribution, such as sub-mm galaxies (Smail, Ivison & Blain, 1997) and red galaxies (Franx et al., 2003). Adelberger et al. (2005) have recently measured the clustering of a new, larger, sample of LBGs: through comparison with n–body simulations they estimate a median halo mass of 