The leader of Reform UK in Wales is standing down after he was arrested and bailed on suspicion of assault and controlling or coercive behaviour.
Dan Thomas, a former Tory councillor, had only been announced as Reform's Welsh leader by Nigel Farage in February.
He was elected as leader of the opposition in May's election to the Welsh parliament, when Reform UK became the second largest party.
However, it emerged on Tuesday that Thomas would not be taking part in the first plenary session of the new Senedd term and questions for the first minister on Tuesday afternoon. Reform said he was absent for “personal reasonsâ€.
In a statement later on Tuesday afternoon, Thomas said: “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.â€
Gwent police said: “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.â€
Thomas, a former Conservative leader of Barnet council in north London, is originally from Blackwood, Caerphilly.
Eyebrows had been raised on Monday when Thomas was notably quiet when it came to commenting on the meeting of the nationalist first ministers of Wales, Scotland and Northern Ireland, who called on Westminster to prepare for independence referendums.
His resignation comes as a major blow to Reform, which has poured significant resources into Wales, where it believes further inroads could be made in traditional Labour strongholds.
However, the perception of Thomas as a figure who was parachuted in by Reform headquarters has caused tensions.
It is believed Farage chose an outsider to the Welsh branch of the party in an effort to distance from its former Welsh leader, Nathan Gill, who was jailed for accepting bribes to make pro-Russia statements in the European parliament.
Since the new Senedd opened in May, there have been frequent reports of infighting in the Reform group, and its performance in the Siambr so far has been notable for unparliamentary conduct.
Thomas led Barnet council between 2019 and 2022, when the north London council was seized by Labour, and defected to Reform last summer.
He stood down in December as a councillor in Finchley – long synonymous with Margaret Thatcher – to move back to his south Wales valleys home town.
In May, Reform won 34 seats at the expense of Labour and the Conservatives in the Welsh parliament's newly expanded 96-seat chamber, behind Plaid Cymru's 43.
Reform had been aiming to become Wales's biggest party, Thomas said, but it still performed better than any Welsh Conservative result on record and managed to increase its vote share from 1% in 2021 to 29% in 2026. With more than a third of the seats, the Senedd is the biggest political platform Reform has had to date.
At almost exactly the same time Thomas announced his resignation, the Reform MS Sarah Cooper-Lesadd said she was defecting to Plaid Cymru – a party nearly on the opposite end of the political spectrum.
She said in a statement: “[Reform UK] … are not serious about governing Wales. They are far more interested in division, opposition and headlines than in finding solutions.
The defection of Cooper-Lesadd coincided with more bad news elsewhere for Reform as three of its councillors resigned from the party on one of its flagship county councils, Durham, after allegations of bullying.
Ken Skates, the leader of the Labour Senedd group, said: “Nigel Farage chose to make Nathan Gill his leader in Wales and he turned out to be a Russian asset. He chose to take £5m from a crypto billionaire that triggered an investigation.
“He chose to meet two men in a pub in Clacton to discuss breaching electoral law. And he chose to make Dan Thomas his leader in Wales, who has now quit suddenly.â€
The Conservative leader, Kemi Badenoch, said on X that “people are innocent until proven guilty†but added that there was “a pattern†in terms of Conservatives who had defected to Nigel Farage's party.
“He took a large number of very problematic people from the Conservatives. Reform is where they belong,†she said.
