Median overionisation profile as a function of the distance from the QSO hosted by a halo as in Fig. 6. We show the influence of the diffuse field on the H ii region for L_νLL = 10³²   erg   Hz^-1   s^-1 at z = 3.0. The upper left plot shows the full radiative transfer simulation, the right plot the one without diffusive radiation, and the lower left plot results using the on-the-spot approximation. The analytical overionisation profile including the SED effects is given by the solid line. The region affected by oversampling (r < 1   Mpc) is marked with a dotted line. The lower right histograms gives the distribution of the overionisation fraction at radii r = 10   Mpc   h^-1 (left) and r = 20   Mpc   h^-1 (right). The solid lines give radiation transfer results, the dashed lines shows results omitting diffusion, and the dot-dashed distribution illustrates results obtained with the on-the-spot approximation. The solid tick indicates the analytical solution.