Dan Thomas led Reform to a breakthrough election result (Image: James Veysey/Shutterstock)
Dan Thomas, the leader of Reform in the Welsh Parliament, has announced he is stepping down from the leadership of the group. Mr Thomas said he had been “reported to the police” at the weekend and was resigning as leader for “personal reasons”.
The Press Association reported Mr Thomas was arrested on suspicion of controlling or coercive behaviour.
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Mr Thomas said in a statement: “It has been the honour of my life to have been the leader of Reform Wales and see this party go from zero to 34 elected members and become the largest opposition group in Welsh history. With deep regret, I am now standing down from this position due to personal reasons.
“Over the weekend, I was reported to the police and was released without charge. I stress that I have done nothing wrong, but I do not want the coming headlines to be a distraction from the fantastic work our Senedd team is doing in holding this government to account. I will continue to serve my constituents in Casnewydd Islwyn and will fully back whoever the group selects as its next leader.”
Gwent Police said in a statement: “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 enquiries.”
Reform won 34 seats to become the biggest opposition party in May’s historic election which saw Labour lose power for the first time since the launch of Welsh devolution in 1999.
Mr Thomas, who took the helm of Reform in Wales in February, led Barnet London Borough Council from 2019 to 2022 as a Conservative councillor.
His resignation comes on the same day that Senedd member Sarah Cooper-Lesadd has defected from Reform to pro-independence Plaid Cymru. The former Conservative parliamentary candidate claimed the “party centrally has no interest in Wales”.
A Reform Wales spokesperson: “As soon as we discovered Sarah Cooper-Lesadd is in favour of Welsh independence and the break-up of the United Kingdom, we planned to expel her from Reform UK.
“Her separatist sympathies are not welcome in our party. Our policy on maintaining the Union is clear. Plaid are welcome to her, she is now in her third party in two years.”
Conservative leader Kemi Badenoch stressed that “people are innocent until proven guilty” but said: “Earlier this year I said Nigel Farage was doing my spring cleaning. He took a large number of very problematic people from the Conservatives. Reform is where they belong.”
Reform’s Welsh Leader Quits After Report to Police and ‘Release Without Charge’
Reform UK’s leader in Wales, Dan Thomas, has stepped down from his position after confirming that he had been reported to police and subsequently released without charge.
Thomas announced his resignation in September, saying that he did not want the circumstances surrounding the police investigation to become a distraction from the work of Reform’s Senedd group. He has denied wrongdoing and stressed that he had “done nothing wrong”. He will remain a Member of the Senedd for Casnewydd Islwyn while the police inquiry continues.
The sudden departure came only months after Reform made a major breakthrough in Welsh politics. The party won 34 seats at the May 2026 Senedd election and became the largest opposition group in the history of the devolved Welsh parliament.
Thomas had been appointed Reform’s Welsh leader in February and subsequently became one of the most prominent figures in the party’s rapidly expanding Welsh operation.
His resignation has therefore created an unexpected leadership challenge at a moment when Reform is attempting to establish itself as a major force in Welsh politics.
Thomas Announces His Departure
Thomas announced that he was standing down after the police incident became public.
In his statement, he said it had been an honour to lead Reform Wales and highlighted the party’s growth from having no elected members to winning 34 seats.
He explained that he had been reported to police over the weekend and had been released without charge. Thomas insisted that he had done nothing wrong, but said he did not want the headlines surrounding the investigation to distract from the work of the Reform Senedd team.
He also made clear that his resignation concerned the leadership position rather than his role as an elected representative.
Thomas said he would continue representing his constituents in Casnewydd Islwyn and would support whoever the Reform group selected as his successor.
That means the political consequences of the incident are currently concentrated on the leadership of Reform Wales rather than Thomas’s elected position.
What Police Said
Gwent Police confirmed that a 45-year-old man from the Aberbargoed area had been arrested on Sunday 13 September.
Police said the arrest was made on suspicion of assault and engaging in controlling or coercive behaviour.
The man was subsequently released on bail pending further enquiries.
Police did not identify the individual by name in their statement.
However, Thomas subsequently confirmed that he was the person who had been reported to police and said he had been released without charge.
The distinction between arrest, charge and conviction is important. An arrest means police are investigating suspected offences; it does not establish guilt. Thomas has denied wrongdoing, and there has been no conviction arising from the allegations.
The investigation remains a matter for the police and any subsequent prosecutorial process.
A Remarkable Election Result
The leadership crisis comes against the backdrop of Reform’s dramatic growth in Wales.
At the May 2026 Senedd election, Reform won 34 seats.
The result transformed the party’s position in the Welsh Parliament and gave it a much larger platform from which to challenge the Welsh government.
Thomas had played a central role in presenting Reform’s political message during the early months of the new Senedd.
The party’s expansion was particularly significant because Welsh politics had traditionally been dominated by Labour, Plaid Cymru and the Conservatives, with smaller parties occupying fewer seats.
Reform’s breakthrough changed the balance of the opposition benches.
Thomas’s departure therefore comes at a sensitive moment for the party as it attempts to turn its electoral success into a stable political organisation.
Another Setback for Reform
Thomas’s resignation was announced on the same day that another Reform Senedd member, Sarah Cooper-Lesadd, defected to Plaid Cymru.
Cooper-Lesadd said she no longer believed Reform’s central organisation was sufficiently interested in Wales and joined the pro-independence party.
Reform rejected her explanation, saying her support for Welsh independence conflicted with the party’s commitment to maintaining the United Kingdom.
The two developments occurring on the same day created questions about Reform’s internal stability.
The party had just achieved its strongest-ever result in Wales, but it was immediately confronted with both a leadership change and the loss of one of its elected members.
Reform representatives have rejected suggestions that the party is in crisis and have instead presented the changes as challenges that can be managed by its enlarged Senedd group.
Nigel Farage’s Response
Reform UK leader Nigel Farage has offered support to the Welsh party during the leadership transition.
Farage has also expressed sympathy for Thomas and described the situation as a difficult personal matter.
He has sought to emphasise that the party can continue its political work despite the disruption.
The support is significant because Reform UK operates with a highly visible national leadership structure, with Farage remaining the party’s most prominent figure.
His response also reflects the distinction between Thomas’s personal circumstances and his future role within Reform.
Thomas remains a Senedd member, meaning the party has not lost his vote or representation in the Welsh Parliament.
Helen Jenner Takes Over
Reform subsequently moved quickly to select a new Welsh leader.
Helen Jenner, who had previously served as the party’s deputy leader in Wales, was announced as Thomas’s successor.
Jenner won an internal vote among Reform’s Senedd members by 17 votes to 15 against Jason O’Connell, according to reporting published after Thomas’s resignation.
Her appointment gives the party a new leadership team only months after its breakthrough election.
Jenner has longstanding connections with Farage’s political movement. She previously stood for the Brexit Party and has also been involved with UKIP.
She now inherits responsibility for leading one of the largest opposition groups in the Senedd.
A New Challenge for Welsh Reform
Jenner’s immediate challenge will be to maintain unity among Reform’s enlarged group.
The party has attracted elected representatives with different political backgrounds, including former Conservatives and politicians who entered public life through Reform’s recent expansion.
Managing such a group can be difficult for any new leader.
Jenner will also have to establish her own public identity while maintaining the broader political direction associated with Reform nationally.
Her first priority is likely to be ensuring that the party’s Senedd members remain focused on their role as an opposition group.
The leadership change also gives Reform an opportunity to move public attention away from Thomas’s police investigation and towards its policy agenda.
Thomas Remains an MS
Although Thomas has resigned as leader, he has not resigned from the Senedd.
He continues to represent the Casnewydd Islwyn constituency and has said that he intends to support the new leadership.
That means the police investigation does not automatically remove him from elected office.
There is also no suggestion in the police statements that he has been convicted of an offence.
His political future will therefore depend on several separate factors: the outcome of the police investigation, his relationship with Reform’s leadership and his own decision about whether to remain active within the party.
For the moment, he remains an elected representative.
Innocent Until Proven Guilty
The circumstances have also prompted renewed discussion about how allegations involving politicians should be reported.
Thomas has publicly denied wrongdoing.
Police have confirmed an arrest and ongoing inquiries, but no conviction has resulted.
That means the allegations should not be treated as established facts.
The principle that a person is innocent until proven guilty remains fundamental to the criminal justice system.
For political parties, however, allegations involving senior figures can create immediate practical problems even before a legal process has reached a conclusion.
A party leader may decide that continuing in the role would create unwanted attention or make it more difficult for colleagues to concentrate on their political work.
Thomas has explicitly presented his resignation in those terms.
What It Means for Reform
The episode illustrates the challenges facing a political party that has expanded rapidly.
Reform has gone from a relatively small presence in Wales to 34 Senedd members within a single election cycle.
That rapid expansion brings greater visibility, but it also means that internal disputes and controversies can have much larger consequences.
The party now needs to demonstrate that its enlarged Welsh group can function effectively under new leadership.
Helen Jenner’s appointment provides an immediate solution to the leadership vacancy, but the longer-term challenge is maintaining cohesion.
The simultaneous departure of Thomas from the leadership and Cooper-Lesadd from the party makes that task more complicated.
The Wider Welsh Political Landscape
Reform’s emergence as a major opposition force has already changed the political landscape in Wales.
The party now has a substantial presence in the Senedd and can play a much larger role in debates over healthcare, education, the economy, housing, transport and the future constitutional direction of Wales.
Its opponents will scrutinise how effectively Reform uses that influence.
Its supporters will expect the party to demonstrate that its election success can be translated into practical political pressure on the Welsh government.
The leadership transition will therefore be watched closely.
What Happens Next?
For Dan Thomas, the immediate issue is the continuing police investigation. He remains an MS and has maintained that he did nothing wrong.
For Reform Wales, Helen Jenner now takes responsibility for leading the Senedd group.
For Nigel Farage and the national Reform leadership, the priority will be maintaining momentum after the party’s historic election result while avoiding internal disputes becoming the dominant story.
The next few months will reveal how successfully Reform adapts to its new position in Welsh politics.
Thomas’s resignation marks an abrupt end to his period as leader, but it does not necessarily end his political career.
He remains an elected member, while the allegations against him remain subject to investigation.
For Reform, meanwhile, the challenge is to ensure that the leadership change becomes a transition rather than a prolonged disruption.
The party entered the new Senedd term with 34 elected members and ambitions to establish itself as a permanent force in Welsh politics. It now has a new leader, an internal challenge to manage and a political reputation to build.
The story surrounding Dan Thomas is therefore not only about one politician’s resignation. It also illustrates the pressures that accompany rapid political growth and the difficulty of managing personal, legal and organisational issues while attempting to consolidate a new position in Welsh public life.