Gary Jones, a senior officer at the GMB general union, which has been a leading campaigner against workplace bullying, presided over a regime in which the union's most vulnerable employees were singled out for the worst treatment, the tribunal was told. The main victims were women.
"All female officers are subject to more vindictive treatment than even the most junior male colleague, the more experienced male colleagues were not exposed to any," the tribunal heard.
On one occasion Mr Jones, the secretary of the union's powerful Lancashire region, became abusive and threatening towards a female union activist and seemed to stop just short of assaulting her, the tribunal said in its judgment.
Mr Jones greeted the idea of holding a seminar on "tackling the workplace bullies" for activists and officials by shouting abuse, according to the tribunal.
Mr Jones, Kevin Curran, the union's former general secretary and three others, as well as the union as a whole, were found guilty of sex discrimination in a 120-page document which paints a picture of a highly dysfunctional organisation, riven from top to bottom with internal tensions between individuals and rival factions.
The union generally, and Mr Jones in particular, were found guilty of seven counts of discrimination against Giovanna Holt, a regional organiser. Discrimination against Maxine Nixon, also a regional organiser, involved the GMB and the four other senior figures and was proven on 18 counts.
Both women complained to the court of a climate of fear in which they were bullied, sworn at and had their work undermined. On one occasion Mrs Nixon came back from sick leave after suffering from "depression and severe anxiety" and came under fire from the people who had caused her anxiety in the first place. She said she felt "humiliated and intimidated".
The Lancashire leader told Mrs Holt that if she had any dealings over the employment tribunal proceedings with Mrs Nixon he would "blow [her] out of the fucking water". Her attempt to organise the seminar on bullying was greeted by a phone call from Mr Jones during in which he said: "What the fuck is this all about? This is about your fucking case isn't it?"
Mr Curran was found to have discriminated against Ms Nixon by failing to deal with her grievance.
The tribunal heard allegations that when Mr Curran was running for the general secretary's job he had "done a deal" with the Lancashire leader. In return for his support he would refuse to take action over Mrs Nixon's allegations of sex discrimination if he won the job. The judgment said there was evidence that the agreement had been struck during several meetings.
Mr Jones and Paul Hoggarth, one of the other respondents, have since been suspended and it is understood will face internal disciplinary hearings.
The victims of the discrimination will learn of any compensation at a date to be fixed.