Plaid Cymru has retained the Hengoed ward on Caerphilly County Borough Council after Anthony Cook won almost half of all votes cast in the five-way by-election.
Cook received 509 votes in the poll held on Thursday 6 August 2026, finishing 138 ahead of Reform UK Wales candidate Kimberley Heath, who placed second with 371.
Welsh Labour’s Dan Kelly came a distant third with 103 votes. Welsh Conservative candidate David Emmins received 21 and Welsh Liberal Democrat David Scullin took 16.
Hengoed by-election result
| Candidate | Party | Votes | Vote share |
| Anthony Cook | Plaid Cymru | 509 | 49.9% |
| Kimberley Heath | Reform UK Wales | 371 | 36.4% |
| Dan Kelly | Welsh Labour | 103 | 10.1% |
| David Emmins | Welsh Conservatives | 21 | 2.1% |
| David Scullin | Welsh Liberal Democrats | 16 | 1.6% |
Vote shares are calculated from the 1,020 votes reported for the five candidates and may not total exactly 100% because of rounding.
- Plaid Cymru majority: 138 votes
- Reported valid votes: 1,020
- Lead over Reform UK: 13.5 percentage points
A verified turnout figure had not been published by Caerphilly County Borough Council at the time of writing. It has therefore not been estimated from the vote total.
Plaid Cymru holds off Reform UK
The result is a Plaid Cymru hold because the vacancy was created by former Plaid councillor Donna Cushing, who was elected to the Senedd in May.
Cook came within a single vote of securing exactly half of the reported valid vote. His 49.9% share was 13.5 percentage points ahead of Heath, although Reform established itself as the principal challenger in a ward it had not contested at the previous full council election.
Labour secured just over one vote in ten. The party had been Plaid Cymru’s only opposition in Hengoed at the 2022 Caerphilly council election, but slipped to third place as Reform entered the contest.
The Conservatives and Liberal Democrats received a combined 37 votes, representing 3.6% of the total between them.
Why was the Hengoed by-election held?
The by-election followed Cushing’s election as a Member of the Senedd. Welsh rules prevent an individual from continuing simultaneously as a county councillor and a Senedd Member, creating a vacancy in the two-member Hengoed ward.
At the 2022 council election, Cushing topped the ward poll with 608 votes and fellow Plaid candidate Teresa Parry won the second seat with 576. Labour’s two candidates received 502 and 494 votes.
That earlier contest allowed electors to vote for two candidates because two seats were available. A conventional swing from 2022 has therefore not been calculated against this single-vacancy by-election, where each elector had only one vote.
Cook becomes Hengoed councillor
Cook is a former soldier who served with the Royal Engineers and the Royal Welsh Regiment, including a tour in Afghanistan. He has subsequently worked in transport and construction-related roles and is reported to work as a surveyor and analyst.
He previously contested the October 2025 Caerphilly Senedd by-election for the Welsh nationalist party Gwlad, receiving 117 votes. His victory in Hengoed now gives him his first elected council seat as a Plaid Cymru representative.
Plaid Cymru group leader Charlotte Bishop congratulated Cook and described him as well known, hardworking and committed to the communities of Cefn Hengoed and Hengoed.
“This victory in Caerphilly demonstrates that more and more people are putting their trust in Plaid Cymru’s positive vision for our communities.”
No response from the unsuccessful candidates has been included because none had been identified in reliable published sources at the time of writing.
Further evidence of changing Welsh politics
The Hengoed result follows other recent local successes for Plaid Cymru in Caerphilly County Borough.
The party retained Penyrheol in a December 2025 council by-election and gained Van from Labour in February 2026. It also won the October 2025 Caerphilly Senedd by-election before the subsequent Welsh Parliament election in May.
Hengoed does not by itself determine how the wider borough or Wales will vote. However, the finishing order adds to evidence of a more fragmented political contest: Plaid retained the seat, Reform displaced Labour as the principal challenger and the two traditional Westminster parties together attracted only 12.2% of the vote.
For Plaid Cymru, the immediate significance is straightforward. The party defended the vacancy and Anthony Cook will succeed Donna Cushing as one of Hengoed’s two representatives on Caerphilly County Borough Council.