BrewDog has been accused of sacking an Asian woman after she voiced her distress when members of the far-right English Defence League met in the London bar where she worked.

The former staff member said members of the EDL had gathered unchallenged at the “punk” brewer’s flagship bar in Waterloo, ahead of a rally to mark St George’s Day on 23 April.

Police went on to arrest 10 people at the event, after groups of men tried to break through cordons in an areas of Whitehall, while glass bottles were also thrown.

The former BrewDog staff member said she had gone to see her manager in a podcast studio located in the bar after she arrived at work to find that suspected members of the EDL were drinking in the bar before the rally.

BrewDog accused her of “aggressive behaviour and use of inappropriate language” after she raised her concerns, according to documents seen by the Guardian.

“This was not the case at all,” Myriam – not her real name – told Tribune magazine, which first reported the story.

“All I said was ‘I can’t fucking believe this. This is fucking unbelievable.’ I didn’t swear at my manager … When I read the accusation, it completely broke me. I was scared, upset, heartbroken. I felt powerless. This is my job. I have bills to pay. I had a breakdown.”

Myriam sent a message to her manager apologising for the strength of her emotions and asked him to put himself “in the shoes of a brown woman in this situation”, adding that her family had faced racial abuse from the EDL when she was growing up.

In a letter to Myriam, BrewDog said it acknowledged her “past trauma and emotional state” but that she had been guilty of serious misconduct worthy of dismissal with notice.

The trade union Unite said it was concerned about BrewDog’s treatment of staff. “We shall be doing everything we can legally and industrially to ensure that our members at this and every Brewdog receive the justice they deserve,” said Bryan Simpson, lead organiser at Unite Hospitality.

While the EDL did not make a booking at the BrewDog bar, Myriam said they were “allowed to sit there and drink before their rally, which always end up violent”.

BrewDog, based in Aberdeenshire, is understood to have been informed by police a day earlier that EDL members were likely to gather in the Waterloo area and might visit the bar. Police told the company not to close the venue and offered assurances that officers would be present.

Myriam said staff were not told about this and said the lack of advance warning was a factor in her reaction. Colleagues were extremely uncomfortable about the presence of the EDL and one was in tears, she claimed.

One member of BrewDog staff who dealt with her disciplinary hearing appeared to be unaware of what the EDL was, she added.

BrewDog, which built a reputation as a “punk” challenger to mainstream beer brands, has faced multiple allegations of poor treatment of staff.

In 2021, the company apologised to former employees who accused the company and its co-founder, James Watt, of fostering a “culture of fear” in which workers were bullied and “treated like objects”.

Watt has since stood down as chief executive, saying he wanted to focus on other ventures, although he remains on the board.

BrewDog told Tribune: “The standards of behaviour we expect from our colleagues are set out in our workplace code of conduct. There was a clear and unacceptable breach of this code in this instance. We followed all relevant processes and complied with our investigation and disciplinary policies, and we stand by our decision.”

The Guardian has approached the company separately for comment.