This article investigates the roles of nominalisation and passivisation within the domain of legal sublanguage, particularly concerning their effects on clarity and interpretative accuracy. Grounded in linguistic frameworks established by Comrie, Thompson, and Lyons, the research elucidates how nominalisation enhances formality and consistency. Conversely, passivisation facilitates a shift in focus from the agent to the action, promoting objectivity. The study examines the prevalence and functional evolution of these linguistic features through a corpus-based analysis of UK Public General Acts from 2003, 2013, and 2023. The findings reveal that while nominalisation and passivisation contribute to precision and neutrality, their excessive application risks diminishing readability for non-specialist audiences. This analysis emphasises the necessity of balancing technical specificity with comprehensibility in legal discourse, aligning with the objectives of the Plain English movement to foster more transparent legal communication.