A referendum on proportional representation held in 2027 would provide a materially larger implementation window than a 2028 date, improving feasibility for a 2029 general election (which must occur by 15 August 2029). The legal framework is clear: Parliament can legislate for a referendum within a single term, as demonstrated by the 2011 Alternative Vote referendum [1], and the result would require implementing primary legislation to take effect.

Using a 10-member constituency model aligned to existing administrative or regional boundaries would significantly reduce administrative burden compared to systems requiring wholesale local boundary redrawing. This approach would avoid the multi-year statutory boundary review process that typically accompanies electoral reform. However, the government would still need to pass primary legislation specifying constituency design, seat allocation, counting rules, candidate nomination procedures, and transition arrangements. Secondary regulations, Electoral Commission guidance, ballot design, IT system updates, staff training, and public information campaigns would all need to be completed within roughly 18–20 months from referendum to polling day.

The 2011 AV precedent is instructive but limited: it retained existing single-member constituencies and required no boundary changes, understating the administrative complexity of most PR models [1]. Even a simplified 10-member system presents specific operational challenges: substantially larger ballots (potentially featuring 70+ candidates), new counting procedures and software, expanded training for returning officers, and logistical changes to printing and ballot management.

Meeting the 2029 deadline would require overwhelming parliamentary majorities, cross-party consensus, pre-agreed legislative drafting, rapid passage of all enabling statutes, no successful legal challenges, and intensive resourcing of the Electoral Commission and local election officials. The Electoral Commission typically recommends that major electoral changes be finalized at least six months before an election [2]. If any stage slips—legislative delays, judicial review, or administrative complications—the 2029 election would likely proceed under the existing First Past the Post system, with implementation deferred to a subsequent election cycle.