Gravitational torque acting on planets in discs with Ṁ = 7 × 10^-8 M_⊙/yr (top) and Ṁ = 8.75 × 10^-9 M_⊙/yr (bottom). The black lines encircle the regions of outward migration. The vertical red lines indicate the ice line at 170 K. The white line represents the zero-torque line of the fits presented in Appendix A. As Ṁ drops, the regions of outward migration shrink so that only planets with lower mass can be saved from inward type-I-migration. Additionally, the orbital distance at which outward migration acts becomes smaller with decreasing Ṁ. This is caused by the shallower gradient in temperature for lower Ṁ discs.