Very recently, the metastable cubic ice phase was renamed to stacking-disordered ice (ice Isd) in order to emphasise the fact that this form of ice contains not only cubic stacking sequences but hexagonal ones as well. In order to fully characterise an ice Isd sample, it is essential to accurately determine the fractions of cubic and hexagonal stacking. So far, this has only been achieved by simulating powder diffraction patterns with varying amounts of cubic and hexagonal stacking. Due to several difficulties and problems associated with this kind of analysis, we propose to develop a new analytical tool for characterising stacking disorder in ice based on pair distribution function analysis. This new tool will help us to develop new strategies for making the stacking-fault free cubic ice as well as its hydrogen-ordered counterpart which has been predicted to be highly ferroelectric.