Reform UK’s Welsh leader resigns after assault arrest

Thomas steps aside

Dan Thomas has resigned as Reform UK's leader in Wales after police arrested and bailed him on suspicion of assault. The change removes the head of the Senedd's second-largest party only months after May's Welsh election and opens a leadership gap in the main opposition group. Thomas said he had done nothing wrong and was stepping aside so that the investigation and accompanying headlines would not distract from his party's work in the Welsh parliament.

Gwent Police said a 45-year-old man from the Aberbargoed area was arrested on Sunday, September 13, and bailed while inquiries continued. The Guardian identified the man as Thomas and reported his resignation on Tuesday. Bail during an investigation is not a charge or finding of guilt. No detailed account of the alleged incident, possible complainant or evidential basis had been made public in the reporting reviewed for this article.

Thomas's absence became apparent when he did not participate in questions to Wales's first minister at the Senedd. Reform initially attributed his absence to personal reasons before he issued a statement confirming he would leave the leadership. The sequence means the political decision is established independently of the unresolved criminal process: Thomas has relinquished his party post, while the police inquiry remains open and the presumption of innocence applies.

A significant opposition vacancy

The resignation has consequences beyond an internal party reshuffle. Reform won 34 seats in the newly enlarged, 96-member Senedd in May, finishing behind Plaid Cymru and ahead of Labour and the Conservatives. Thomas had therefore become leader of the opposition at a moment when Reform was investing heavily in Wales and targeting former Labour strongholds. Replacing him will require the party to decide whether to promote a member of its new Senedd group or bring in another figure closely aligned with its UK leadership.

Thomas had only been named Reform's Welsh leader in February. Originally from Blackwood in Caerphilly, he previously led Barnet council in north London as a Conservative before defecting to Reform and returning to south Wales. His rapid rise had already generated complaints that the national party had imposed a candidate without deep roots in its emerging Welsh organisation. The vacancy may reopen those tensions over local autonomy and central control.

The immediate questions are procedural. Reform must identify who will lead its Senedd group, whether Thomas retains his seat and ordinary party membership, and how responsibilities at first-minister questions will be reassigned. Police must decide whether the investigation produces charges, no further action or a prolonged period of bail. Those outcomes should be kept separate from the confirmed political fact: Wales's principal opposition party has lost its leader at an early stage of the new parliamentary term.