  We investigate colour selection techniques for high redshift galaxies in the
UKIDSS Ultra Deep Survey Early Data Release (UDS EDR). Combined with very deep
Subaru optical photometry, the depth (K_AB = 22.5) and area (0.62 deg^2) of the
UDS EDR allows us to investigate optical/near-IR selection using a large sample
of over 30,000 objects. By using the B-z, z-K colour-colour diagram (the BzK
technique) we identify over 7500 candidate galaxies at z > 1.4, which can be
further separated into passive and starforming systems (pBzK and sBzK
respectively). Our unique sample allows us to identify a new feature not
previously seen in BzK diagrams, consistent with the passively evolving track
of early type galaxies at z < 1.4. We also compare the BzK technique with the
R-K colour selection of Extremely Red Objects (EROs) and the J-K selection of
Distant Red Galaxies (DRGs), and quantify the overlap between these
populations. We find that the majority of DRGs, at these relatively bright
magnitudes are also EROs. Since previous studies have found that DRGs at these
magnitudes have redshifts of z ~ 1 we determine that these DRG/ERO galaxies
have SEDs consistent with being dusty star-forming galaxies or AGN at z < 2.
Finally we observe a flattening in the number counts of pBzK galaxies, similar
to other studies, which may indicate that we are sampling the luminosity
function of passive z > 1 galaxies over a narrow redshift range.
