  The Millennium Galaxy Catalogue (MGC) is a deep ($\mu_{\rm B,lim}=26$ mag
arcsec$^{-2}$), wide field CCD imaging survey, covering 37.5deg$^2$ and is
completely contained within the 2dFGRS and SDSS-EDR. We compare the photometry
and completeness of the 2dFGRS and the SDSS-EDR with the MGC. We have also
undertaken a photometric comparison to SCOS and SDSS-DR1 data.
  We find that $B_{MGC}-B_{2dF}=0.035$ mag with an uncertainty of 0.142 mag per
galaxy, $B_{MGC}-B_{SCOS}=0.032$ mag with an uncertainty of 0.108 mag,
$B_{MGC}-B_{SDSS-EDR}=0.032$ mag with an uncertainty of 0.094 mag, and
$B_{MGC}-B_{SDSS-DR1}=0.039$ mag with an uncertainty of 0.086 mag. We find that
high surface brightness 2dFGRS galaxies are systematically too faint. In the
SDSS there is a weak non-linear scale error, which is negligible for faint
galaxies. LSBGs in the SDSS are systematically fainter.
  We find that the 2dFGRS catalogue has 5.2% stellar contamination, 7.0% of
objects are resolved into 2 or more by the MGC and is 8.7% incomplete compared
to the MGC. From our all object spectroscopic survey we find that the MGC is
itself misclassifying 5.6% of galaxies as stars, hence the 2dFGRS misses 14.3%
of the galaxies. The SDSS-EDR galaxy catalogue has 1.3% stellar contamination
and 5.3% of galaxies misclassified as stars, and is 1.8% incomplete compared to
the MGC. Altogether 7.1% of the total galaxy population are missing from the
SDSS-EDR catalogue from incompleteness or misclassification.
