
Wales Governance Centre
Cardiff University academic centre specialising in Welsh governance and devolution research
Last refreshed: 22 May 2026 · Appears in 1 active topic
What share of the vote does a party need to win a Senedd seat under the new PR system?
Timeline for Wales Governance Centre
Mentioned in: ap Iorwerth's six-power Wales Bill ask
UK Local Elections 2026Mentioned in: Plaid takes Cardiff after 27 years
UK Local Elections 2026Mentioned in: Wales holds first 96-seat PR Senedd election 7 May
UK Local Elections 2026Mentioned in: Welsh Labour collapses to nine seats
UK Local Elections 2026Mentioned in: Wales Greens fall from 10 to 2
UK Local Elections 2026What is the Wales Governance Centre?
What percentage of votes does a party need to win a Senedd seat?
What is the consolidation not conversion thesis in Welsh politics?
Background
The Wales Governance Centre (WGC) is an academic research centre at Cardiff University, established to study Welsh politics, devolution, public policy and constitutional change. It is the leading academic institution tracking the Senedd's transition to closed-list PR ahead of the 2026 election. The WGC's work on seat allocation under the new D'Hondt system produced the widely cited estimate that a party needs approximately 12 per cent of a constituency vote to secure a single Senedd seat.
In April 2026, WGC researchers described Welsh political realignment as consolidation not conversion: progressive voters are moving from Labour to Plaid Cymru within the Welsh/Left bloc, while conservative voters are moving from Welsh Conservatives to Reform UK within the British/Right bloc. The analysis drew on aggregate polling, candidate data, and historical electoral returns. Researchers described the 2026 Senedd election as the most consequential since 1999. The WGC also tracked the constitutional consequences of the gender-zip bill withdrawal, which removed a mechanism for enforcing candidate gender balance before the new system debuted.
Post-7 May, WGC's analysis has focused on the Plaid-Green minority government formation, describing the confidence-and-supply arrangement as historically novel for Wales and mapping the constitutional powers Rhun ap Iorwerth's administration is seeking to transfer from Westminster. The WGC's documentation of the Welsh PR transition is building an evidence base that will be referenced in future UK electoral-reform debates, given England's continued use of first-past-the-post.