Many high-stakes qualifications include non-exam assessments that are marked by teachers. Awarding bodies then apply a moderation process to bring the marking of these assessments to an agreed standard. Comparative Judgement (CJ) is a technique where two (or more) pieces of work are compared at a time, allowing an overall rank order of work to be generated. This study explored the practical feasibility of using CJ for moderation via an experimental moderation task requiring judgements of pairs of authentic portfolios of work. This included aspects such as whether moderators can view and navigate the portfolios sufficiently to enable them to make the comparative judgements, on what basis they make their decisions, whether moderators can be confident making CJ judgements on large pieces of candidate work (e.g., portfolios), and the time taken to moderate.