Normalised distribution of galaxy rest-frame UV colour in VIPERS in the redshift range 0.5 ≤ z ≤ 1.2 (points). Statistical uncertainties include contributions from Poissonian shot noise and cosmic variance, estimated using the linear bias relation with b = 1.4 (see Appendix D). The best-fit models (Eq. (1)) are shown as black continuous lines. Contributions to the model from the galaxies belonging to the blue cloud, red sequence and green valley are plotted as blue dashed, red dash-dotted and green dotted lines, respectively.