  Motivated by the current constraints on the epoch of reionisation from recent
cosmic microwave background observations, ionising background measurements of
star-forming galaxies, and low redshifts line-of-sight probes, we propose a new
data-motivated parameterisation of the history of the average ionisation
fraction. This parameterisation describes a flexible redshift-asymmetric
reionisation process in two regimes that is capable of fitting all the current
constraints.
