We have compiled a sample of similar to 9600 bright, i less than or equal to 18.95, red, b(J) - r > 2, candidate galaxies in an area of 220 deg(2). These are luminous, L > L*, field early-type galaxies with redshifts 0.3 less than or similar to z less than or similar to 0.6. We present a redshift catalogue of a subsample of 581 targets. The galaxies were selected according to their broad-band b(J)ri colours from United Kingdom Schmidt Telescope plates, and have a surface density on the sky of only similar to 50 deg(-2). Such luminous field galaxies are virtually absent from published redshift surveys and the catalogue provides a large sample of the most luminous normal galaxies, at cosmological distances. The statistical properties of the galaxy spectra, including absorption-line and emission-line measures, are presented and a composite spectrum constructed. The nature of the sample, combined with the relatively bright apparent magnitudes, makes the galaxies suitable targets for several key investigations in galaxy evolution and cosmology.