Colour–magnitude diagram showing the relationship between the rest-frame B − V colour and the absolute magnitude in the B band for AGN in the SXDS (red stars) and GWS (black crosses) fields with redshifts z ≤ 2. The sample of AGN is compared with a sample of normal galaxies from the CDF-S field (Wolf et al. 2001, 2004, 2008) represented by contours. The grey scales of the contours are scaled to the data, where the darkest and brightest show the highest and the lowest density of the sources, respectively. The dashed line shows the Melbourne et al. (2007) separation between the red sequence (B − V > 0.6) and blue cloud (B − V < 0.6) galaxies. Median error bars are 0.0083, and 0.0325 for the absolute magnitude in the B band, and 0.0198, and 0.0489 for the B − V rest-frame colour, in the SXDS and GWS fields, respectively.