Nigel Farage has unveiled Helen Jenner as the newly-elected leader of Reform in Wales, replacing Dan Thomas after his arrest on suspicion of assault and controlling or coercive behaviour.

Speaking on the steps of the Senedd in Cardiff on Monday, Farage said: “I’ve known Helen for many, many years. She is a determined campaigner.”

Farage said he was sorry for former leader Thomas’s “personal difficulties” and that it had been untenable for him to continue, adding: “We could have done without this bump in the road.”

Jenner, who served as Thomas’s deputy alongside her role as Senedd member for Bangor Conwy Môn, said it was an honour to be elected to the top job.

A leadership vote was held by Reform’s 33 Senedd members on Monday morning, and Jenner confirmed that her colleague Jason O’Connell had stood against her.

O’Connell had not been expected to stand, and there had been no vote of the wider party membership.

Speaking to reporters outside the Senedd, Farage said there would be a vote for a new Welsh deputy leader to replace Jenner on Tuesday.

Jenner had been interim leader and favourite to replace Thomas, with sources telling BBC Wales that “very senior” Reform figures had backed her.

She is a married mother-of-two from Anglesey and had spent 15 years working as a teacher.

A fluent Welsh speaker, Jenner had been a member of all Farage’s parties since UKIP, and stood for the Brexit Party in the 2019 Senedd election.

For the first time all of the Senedd’s group leaders now come from north Wales, with two from the island of Anglesey where Welsh First Minister Rhun ap Iorwerth is also from.

Reform’s ex-Welsh leader Thomas stepped down on 15 September after his arrest on suspicion of assault and controlling or coercive behaviour. He was bailed pending further enquiries, and denies doing anything wrong.

He was not on the steps of the Senedd for Jenner’s unveiling as leader, but he had been among the Reform Senedd members who met in Cardiff Bay last week to discuss their next steps, with a party official from London attending to oversee proceedings.

Farage said that it had been “pretty much untenable for him to continue as leader”.

He said Jenner was “someone I trust”.

Farage said the party will carry on “as if nothing had happened, waiting for Dan, who is going to stay a member of this place, to come back more actively with us”.

Farage told BBC Wales he was happy for Thomas to continue as a Reform MS while the investigation continues.

“He hasn’t been charged for anything,” he said.

“We’re going to crack on being a voice of opposition here in Cardiff. We’re going to crack on being really active when it’s in session, and we’re going to crack on getting ready to fight 1,200 council seats which come up all across Wales for local government next month.”

Jenner told BBC Wales there were a “few things” Reform needed to change, including giving members more of a say on policy.

“We’ve done an excellent job of holding the Welsh government to account so far,” she said.

“We’ve gained consensus across the chamber on some issues and we’ve really held them to account”.

She denied the party had a “unity issue” after James Evans claimed last week he would have had “majority” support to stand as leader had he not ruled himself out.

“I think that it was a really difficult time for us,” Jenner said of the last week.

“But I think we are really united in terms of what we’re trying to achieve here.”

The news that Thomas had resigned as leader coincided with the separate decision by Reform’s Sarah Cooper-Lesadd to defect to Plaid Cymru.

Farage said he could “not tell you what is going on in the mind of Sarah Cooper-Lesadd” and that her defection “just doesn’t make any sense”.

A Welsh Labour spokesperson said: “Just months after the Senedd election, Reform has already seen its leader resign and one of its members leave the party. Alongside departures from its council groups in England, that raises serious questions about its stability and ability to deliver for the people it represents.”

Additional reporting from Adam Hale