Fata Lemes, 33, worked at the Rocket Bar in Mayfair for eight days last year and was told the loose-fitting uniform for female members of staff would change for the summer. Men and women wore black shirts and trousers or skirts, but in the warmer weather female workers would wear sleeveless red dresses of mid-thigh length. She told an employment tribunal in central London the figure-hugging dress was "disgusting".
A panel led by employment judge Anthony Snelson found she held "views about modesty and decency which some might think unusual in Britain in the 21st century". But it upheld her claim that bar owners Spring and Greene had discriminated against her on the grounds of her gender.
They said of the dress: "Plainly, it related to her sex. It was gender-specific. The respondents did not introduce a summer uniform for male waiting staff. Unlike the women, the men were not required to switch to brightly coloured, figure-hugging garb."
Forcing her to wear the dress if she wanted to continue working at the bar "violated her dignity", the panel decided, and created a "humiliating" environment. It found: "Her perception was that wearing the dress would make her feel as if she was on show, as if she was being presented as one of the attractions that the Rocket Bar was offering its customers.
"In our view that perception was legitimate and not unreasonable. We are reinforced in this conclusion by the striking contrast between the dress and the dark, loose-fitting attire which would remain the men's uniform."
Lemes told bosses she felt unable to wear the dress and it became clear neither side would compromise, the panel found. It rejected her claims that she was sacked from the bar and became prey to discrimination - for example, that she did not receive tips for the shifts she worked.
Bob Fahy, a solicitor at Matthew Arnold & Baldwin LLP, said the case was a useful reminder to all employers of the kind of pitfalls that can arise when implementing a dress code at work.
"Dress codes that are applied even-handedly between men and women for the purposes of maintaining conventional appearances are unlikely to fall foul of sex discrimination legislation," he said.
"This does not require an identical dress code for men and women (for instance a policy that required men to wear ties and women to "dress appropriately and to a similar standard" has been held to be lawful). However, the greater the difference in the kind of clothing that men and women are required to wear, the greater the risk of a finding that the policy is discriminatory on the grounds of sex."