Left-hand panel: photometric versus spectroscopic redshift for SWIRE-EN1 sources (UgriZ+ 3.6, 4.5 μm), using at least 6 bands and requiring r < 23.5, S(3.6) > 7.5 μ Jy. Most of the spectroscopic redshifts at z > 0.5 are from the programme of Berta et al. (2007) and Trichas et al. (in preparation). Right-hand panel: photometric versus spectroscopic redshift for SWIRE-Lockman sources (Ugri+ 3.6, 4.5 μm), using six bands and requiring r < 23.5, S(3.6) > 7.5 μJy. Most of the spectroscopic redshifts at z > 0.5 are from the programme of Berta et al. (2007) and Smith et al. (in preparation).