Full Breakdown
Reform UK Wales in Turmoil After Leader’s Arrest and MS Defection
By Drooid · · How we work
Core Event: Arrest, Resignation and Defection
On Sunday 13 September, Gwent police arrested Dan Thomas, a 45-year-old former Conservative councillor from the Aberbargoed area, on suspicion of assault and engaging in controlling or coercive behaviour. He was bailed pending further inquiries. The following day Thomas announced his resignation as Reform UK’s leader in the Senedd, citing “personal reasons” for his absence from the first plenary session.
Background & Context
Reform UK entered the May 2026 Senedd election as a newcomer, positioning itself as a challenger to Labour and the Conservatives in traditional Labour heartlands. The party secured a historic share of the vote, rising from 1 % in 2021 to 29 % in 2026, and became the second-largest party in the 96-seat chamber. Nigel Farage appointed Thomas—an outsider from the party’s national leadership—as the Welsh leader in February, a move intended to distance the Welsh branch from former leader Nathan Gill, who was later jailed for bribery. Since the Senedd opened, Reform’s group has been marked by reports of internal discord and unparliamentary conduct.
Data & Statistics
- Vote share increase: 1 % (2021) -> 29 % (2026).
- Seats reported for Reform UK: 34 seats (one source) vs. 33 seats after Cooper-Lesadd’s defection (another source).
- Plaid Cymru seats: 43 seats (one source) vs. 44 seats after the defection (another source).
Official Statements & Responses
- A Reform UK spokesperson said the party had “planned to expel” Cooper-Lesadd for supporting Welsh independence, emphasizing that the defection was “not taken lightly.”
- Plaid Cymru’s Senedd group chair, Marc Jones, described Cooper-Lesadd’s arrival as motivated by a desire to serve vulnerable communities and criticized Reform’s “politics, rhetoric and values.”
Criticism & Opposition
- Labour Senedd leader Ken Skates accused Nigel Farage of repeatedly “choosing” problematic figures, linking Thomas’s resignation to a series of controversial decisions by Farage’s leadership.
- Conservative leader Kemi Badenoch highlighted a perceived trend of “problematic people” moving from the Conservatives to Reform UK, suggesting a pattern of instability.
Conflicting Reports & Gaps
- Seat counts: The Guardian reported that Reform UK won 34 seats and Plaid Cymru held 43 seats after the May election. The BBC reported that, following Cooper-Lesadd’s defection, Reform UK holds 33 seats and Plaid Cymru holds 44 seats.
- No further details have been released regarding the outcome of the police investigation into Thomas’s alleged assault.
Verbatim Quotes
- “On Sunday 13 September, a 45-year-old man, from the Aberbargoed area, was arrested on suspicion of assault and engaging in controlling/coercive behaviour. He has been bailed pending further inquiries.” — Gwent police
- “He was not in any way penalised for the actions that he did in the chamber.” — Sarah Cooper-Lesadd