Colour–magnitude diagram showing the relationship between the rest-frame B − V colour and the absolute magnitude in the B band for different morphological types, using a sample of X-ray selected AGN in the SXDS (red stars) and GWS (black crosses) fields. All AGN having redshifts z ≤ 2.0 are presented, compact (top), early- (bottom left) and late-type (bottom right) galaxy hosts. Morphological classification of active galaxies in the SXDS field is described in Sect. 3, while morphological classification of active galaxies in the GWS field is described in Pović et al. (2009a). The sample of AGN is compared with the sample of normal galaxies in the CDF-S field (Wolf et al. 2001, 2004, 2008) represented with contours. 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 galaxies belonging to the red sequence (B − V > 0.6) or to the blue cloud (B − V < 0.6).