Left: the K-band luminosity function for powerful radio galaxies (sample B, L > 10²⁴ W Hz^-1) and normal galaxies. We also show Schechter function fits to galaxies from the UKIDSS Large Area Survey (Smith et al. 2009) and the 6dF Galaxy Survey (Jones et al. 2006). The number density of powerful radio galaxies peaks at an absolute K-band magnitude of −25.5 (using h = 0.72). Right: the fraction of radio galaxies as a function of galaxy luminosity. We see at rapid increase from zero for L < 5 × 10¹⁰+L_⊙ to  ~ 20% for the brightest galaxies. We also show the fraction of radio-loud AGN (with the same minimum radio luminosity) in SDSS (Best et al. 2005a), converted to the K-band luminosity using a mean mass-to-light ratio M/L_K = 0.8 (Bell et al. 2003).