W1 − W2 vs z_AB − W1 and J − W2 vs z_AB − W1 colour–colour diagrams of all the T subdwarf candidates in Table 5, except ULAS1319, which has neither W1 nor W2 magnitudes, and ULAS1316 whose photometry was contaminated by a background galaxy. For WISE0833 and WISE0013, we used arrows to indicate the lower limit of the W1 magnitude. We also included normal M, L, and T sequences; sub-L dwarfs; and a Y dwarf. All the T dwarfs, the Y dwarf, and our objects have error bars. In the first diagram, the candidates clearly separate into three groups.