Disc evolution for a viscous disc with internal photoevaporation due to X-rays, using the nominal photoevaporative mass loss rates from table 1 and an α parameter of α = 10⁻³, corresponding to an increase by a factor of 10 compared to our nominal viscosity. The host star masses vary from 0.5 M_⊙ (on the left) to 0.1 M_⊙ (on the right). Top: Gas surface density as a function of disc radius and time. Bottom: Gaseous C/O ratio as a function of disc radius and time. Colour coding, plotting, and remaining simulation parameters are indicated as in figure 3.