The gay, former HSBC investment banker who is claiming unfair dismissal told an employment tribunal that he secretly filmed his disciplinary appeal hearing because he did not trust his employer.

Peter Lewis, claims he was sacked by the bank because he is gay. He was dismissed by the banking giant for “gross personal misconduct”. The incident in question relates to an encounter between Mr Lewis and another male employee of the bank, which ultimately resulted in a complaint of “sexual harassment”.

Mr Lewis told the tribunal that he made a DVD recording of his disciplinary appeal hearing because he had lost faith in his employer.

“I felt I was being stitched up,” Mr Lewis told the hearing. “I lost all trust and confidence in the appeal process.”

In November, 2004, the former equity head of equity trading, says he was approached and harassed by a man who demanded to know his name at his work’s health club. He said: “As a gay man, I am aware that my sexuality can provoke hostile reactions from people, I just wanted him to go away. I therefore gave him a name which was not mine and which I made up on the spot.”

He chose not to report the confrontation, but five days later was summoned to a meeting where he was told a man had accused him of ogling and masturbating in front of him, “The implication was that I had been ‘coming on’ to someone in the changing rooms.

“However, I was, and still am, in a very happy, stable, long-term relationship which has lasted ten years. I had no need or desire to behave in such a way.”

Mr Lewis told the tribunal his sexuality had provoked a “considerable amount of interest and comment” in the City, including abusive phone calls to his home and office. He claims some workers felt it was “inappropriate that someone occupying such a senior position should be gay”.

He said: “Others would make homophobic comments either directly to me or, more usually, behind my back to my manager or colleagues. The situation has improved but discrimination and homophobia in the financial services industry has not been eliminated.”

The former senior banker may have to accompany the employment tribunal to the bank’s offices. The Stratford tribunal will visit the Canary Wharf offices where the claim of sexual harassment is alleged to have taken place. The trip may involve a re-enactment of the encounters between the former senior banker and a male colleague.

It is believed to be the biggest case of its kind to have reached an industrial tribunal since December 2004 when sex discrimination rules applied to gays and lesbians.

Mr Lewis was believed to have earned around £1m a year. His lawyer Alison Downie, of solicitors Bindman and Partners, said her client was dismissed “because HSBC discriminated against him because of his sexual orientation as a gay man.”

The bank denies his claims, a spokesman for the bank told the Evening Standard in October that Mr Lewis was dismissed “after a lengthy disciplinary proceeding”.

The hearing continues.