  Reionisation blurring is a non-linear correction to the cosmic microwave
background that acts similar to weak gravitational lensing and that can be
computed from linear perturbations through a blurring potential. Its impact on
the cosmic microwave background is roughly two order of magnitude smaller than
that of lensing, in isolation. But the blurring potential is strongly
correlated with the lensing potential thereby generating a potentially
observable cross-correlation. We compute for the first time the inclusive
impact of reionisation blurring on the temperature angular power spectrum and
discuss how much it could induce lensing anomalies
