An internal investigation into the behaviour of a senior fire officer upheld “a number” of “factual allegations” made against him in a harassment row, a document submitted to an employment tribunal has said.

Stuart Millington’s appointment to be interim chief fire officer in south Wales by Welsh government commissioners was surrounded in controversy after news he was facing an employment tribunal came to light.

Watch manager Dafydd Roberts is seeking compensation over claims North Wales Fire Service penalised him for trade union activity – with a witness claiming of a “toxic” culture.

North Wales Fire and Rescue Service have rejected the claims, and is seeking to have the case thrown out.

Evidence provided to the tribunal gives more detail on an internal investigation referenced by Plaid Cymru leader Rhun ap Iorwerth in the Senedd last week.

A preliminary hearing for the tribunal, where Mr Millington and another fire officer, head of control Ros Thomas, are named as respondents, took place on Thursday.

Mr Millington was installed in South Wales Fire and Rescue Service following a separate bullying and harassment scandal. He is on secondment from his job as assistant chief fire officer.

The claim concerns a series of events that followed the setting up of a group chat by Mr Roberts, in his capacity as a union representative, on Telegram with other watch managers on 18 March 2023, over concerns regarding an appointment to a job.

Mr Roberts claims that a relative of a senior officer had been appointed to a role without advertisement or competitive process.

In a statement, the claimant alleged Ms Thomas, “in an intimating and bullying manner”, proceeded to question control room operators on whether they agreed with the sentiments expressed.

He said Mr Millington summoned him to a disciplinary meeting on 27 March.

Mr Roberts refused to attend without a representative of the Fire Brigades Union (FBU), and claimed Mr Millington told him he was refusing a “reasonable management request”.

Leaving work because of the stress of the situation, he claimed Mr Millington scheduled a meeting the following day.

Mr Roberts claimed Mr Millington made “false representations” to an FBU official “to persuade the clamant to attend a meeting without union representation”.

He claimed in a further meeting Mr Millington had “adopted a very intimidating and bullying manner, raising his voice and speaking to the claimant in an accusatory and exasperated tone”, pressing Mr Roberts to agree he had committed misconduct “by raising the matter of nepotism”.

Evidence submitted to the tribunal includes an investigation, commissioned by North Wales fire service, conducted by an outside company into concerns raised about Mr Millington.

It said his behaviour fell “below those expected or those that would have been helpful” in eight areas.

They included:

• Notice not having been given to Mr Roberts of Mr Millington’s plan to speak to him on 27 March
• Using the term “organisational terrorism” in conversation with North Wales FBU chair Stuart Stanley
• Raising his voice in a meeting on 5 April 2023, asking Mr Roberts why he was not wearing uniform at the meeting and not providing information directly to Mr Roberts “In respect of his plan for an desired outcome” from that meeting

“Evidence has been found that [Mr Roberts] felt intimidated by [Mr Millington’s] actions towards him,” the report said.

“As the issues arose as a result of [Mr Roberts’] actions as a trade union representative, the investigator therefore believes that there is a prima facie case that [Mr Millington’s] actions against [Mr Roberts’] may amount to discrimination/harassment on the grounds of trade union activity.”

It said: “The investigation has upheld a number of the factual allegations made by [Mr Roberts] against [Mr Millington].

“The conduct complained of (if upheld) may also amount to bullying and harassment which amounts to misconduct or gross misconduct,” the report added.

The respondents denied the allegations made by Mr Roberts.

They had claimed Ms Thomas had been “concerned by the tone taken by the claimant” in the Telegram messages.

On Thursday, a preliminary hearing for the tribunal sitting heard from former colleagues and FBU officials.

Representing the respondents, Jonathan Walters accused FBU south Wales brigade chair Gareth Tovey of a “political campaign that the FBU are indulging in”, which Mr Tovey denied.

Duncan Stewart Ball, regional secretary of the FBU, said on visits to the service’s control room “it was clear members of staff were scared and worried to speak out”.

“We were informed repeatedly that they would be questioned by [the control management team] following our visit, as to what was said and by whom”.

Ruth Bateman, a brigade organiser of the FBU, said in her statement she had taken phone calls from numerous FBU control members asking for assistance and support “as they felt thought they couldn’t approach members of [the control management team] and supporting members who have described the culture in control as toxic and not a nice working environment”.

North Wales fire service has applied to have the case thrown out, arguing Mr Roberts waited too long in making his claim.

Tribunal judge Stephen Povey adjourned the hearing to consider their application.