An employment tribunal has begun hearing the case of an ex-HSBC bank executive who claims he was wrongly dismissed for being gay.
HSBC says it will "vigorously defend" the allegations
Peter Lewis, previously global head of equity trading at the banking giant, claims that his sexual orientation was the motive for his dismissal.
The tribunal heard that the sacking was "inevitable" once Mr Lewis was accused of sexual harassment by a colleague.
HSBC has rejected allegations of discrimination.
The bank has said that Mr Lewis was fired for gross misconduct after a member of staff complained of sexual harassment.
Mr Lewis is thought to be claiming up to £5m ($8.7m) in compensation.
Specific laws barring discrimination on grounds of religion or sexual orientation came into force in late 2003, and there have been a number of successful claims made against employers since then.
"These cases are becoming more prevalent," said Jo White, an assistant solicitor at employment law specialists Thompsons.
"People are gaining the confidence to come forward, although a lot of these cases are settled in advance because companies don't want their dirty linen aired in public."
Employment lawyers claim Mr Lewis' case is the first high-profile case involving a City institution.
"My client is keen to have his case heard by the tribunal, pleased that the law now enables him to bring his claim and maintains that he would not have been dismissed but for his sexual orientation," said Alison Downie, Mr Lewis' solicitor at Bindman & Partners.
HSBC "utterly rejects" Mr Lewis' allegations, and claims he was given the chance to put his side of the story.
"The dismissed employee was treated in the same way as any other employee facing a complaint of sexual harassment by another member of staff," said an HSBC spokesman.
"We believe in doing what is right and not what is expedient and our sexual harassment policy applies to all staff."
Mr Lewis had only been working for HSBC two months before making the allegations.