  We compare observations of the high redshift galaxy population to the
predictions of the galaxy formation model of Croton et al. (2006) and De Lucia
& Blaizot (2006). This model, implemented on the Millennium Simulation of the
concordance LCDM cosmogony, introduces "radio mode" feedback from the central
galaxies of groups and clusters in order to obtain quantitative agreement with
the luminosity, colour, morphology and clustering properties of the present-day
galaxy population. Here we construct deep light cone surveys in order to
compare model predictions to the observed counts and redshift distributions of
distant galaxies, as well as to their inferred luminosity and mass functions
out to redshift 5. With the exception of the mass functions, all these
properties are sensitive to modelling of dust obscuration. A simple but
plausible treatment agrees moderately well with most of the data. The predicted
abundance of relatively massive (~M*) galaxies appears systematically high at
high redshift, suggesting that such galaxies assemble earlier in this model
than in the real Universe. An independent galaxy formation model implemented on
the same simulation matches the observed mass functions slightly better, so the
discrepancy probably reflects incomplete galaxy formation physics rather than
problems with the underlying cosmogony.
