c$_{1}$ c 2 0 0 . 2 0 . 4 0 . 6 0 . 8 1 1 . 2 0 0 . 1 0 . 2 0 . 3 0 . 4 0 . 5 0 . 6 0 . 7 0 . 8 I N$_{1}$ I+N$_{2}$ N$_{1}$+N$_{2}$ I+N$_{1}$+N$_{2}$ N$_{2}$ FMT (a) c$_{1}$ c 2 0 0 . 2 0 . 4 0 . 6 0 . 8 1 1 . 2 0 0 . 1 0 . 2 0 . 3 0 . 4 0 . 5 0 . 6 0 . 7 0 . 8 N$_{1}$+N$_{2}$ I+N$_{2}$ N$_{2}$ I+N$_{1}$+N$_{2}$ I+N$_{1}$ N$_{1}$ I Onsager (b) FIG. 4: Phase diagrams for λ = 2. (a) shows the phase behaviour in the ( c$_{1}$, c$_{2}$ ) representation for Onsager theory and (b) for FMT. (c) shows the phase behaviour in the ( x, p $^{∗}$) representation for Onsager theory and (b) for FMT. The topology is the same for Onsager theory and FMT. Solid lines denote the binodals and the thinner solid lines denote tie lines. As well as I - N coexistence, there is now coexistence between two nematic phases; the N - N phase ends in a critical point (depicted as a shaded circle) in both Onsager theory and FMT, though the critical point is at lower densities for FMT. The dashed lines denote the I - N spinodals but we do not show the location of the N - N spinodals on these phase diagrams. There is also I - N - N coexistence. In (a) and (b) this triple point is represented by a region bounded by dotted lines, the vertices of which are the pure phases. In (c) and (d) this region is collapsed onto a triple line, shown here with a dotted line. 34