The leader of Reform UK in Wales, Dan Thomas, has resigned following his arrest on suspicion of assault and coercive behaviour over the weekend. Thomas, who was appointed Welsh leader in February, led the party to become the official opposition in the Senedd during the May elections, marking a significant gain for Reform UK in Welsh politics.

In a statement, Thomas expressed regret over his decision to step down, citing personal reasons. He emphasized that he was released without charge and denied any wrongdoing, stating his desire to avoid distracting from the party’s work in holding the Welsh government accountable. He confirmed he will continue to represent his constituents in Casnewydd Islwyn and pledged his support to whoever is chosen as his successor.

Gwent police confirmed the arrest of a 45-year-old man from the Aberbargoed area on suspicion of assault and coercive behaviour. The individual was released on bail pending further inquiries.

Thomas, who had previously served as Conservative leader of Barnet council in London, took leadership of Reform UK Wales ahead of the May elections, where the party secured 34 seats, becoming the largest opposition group in Senedd history.

On the same day as Thomas’s arrest and resignation, Sarah Cooper-Lesadd, a Reform UK member of the Senedd representing Pen-y-bont Bro Morgannwg, announced her defection to Plaid Cymru. Cooper-Lesadd criticized Reform UK’s approach to Welsh politics, stating the party lacked genuine interest in addressing Welsh issues. She described Reform’s Senedd group as more focused on opposing the government and generating headlines rather than developing solutions, and suggested that the party was primarily a platform to advance former UKIP leader Nigel Farage’s ambitions at the UK level.

Reform UK has yet to announce the process for selecting a new leader in Wales as it continues to navigate internal challenges ahead of ongoing parliamentary work.