Just what is a formal professional dress code? For men, it's always easy: Dark suit, white or blue shirt, a tie, and dark shoes and socks. For women? Not so much. Can you wear pants? How short of a skirt is too short? Do you need a jacket? Is a nice cardigan the equivalent of a suit coat?

And let's talk about shoes. Flats? Heels? Open-toed okay? Sandals? What about nylons? And are tights the same as nylons and what about bare legs?

Companies disagree on these things and one woman, Nicola Thorpe, found herself sent home from a London office of PwC for not wearing two to four-inch heels. Her job involved a lot of walking around the office and she, understandably, didn't want to wear heels. Thorpe was a temp working directly for Portico, who had and enforced the rule. It wasn't a PwC rule.

Two years after Thorpe was sent home, the UK Parliament released a report that said Portico had violated the law in requiring a woman to wear high heels. In additional to parliamentary support, Thorpe got the support of 150,000 signatures opposing the sexist and sometimes painful requirement.

The New York Times reports that Portico announced a revamped dress code this week.

Its old code had warned employees against such things as greasy or highly gelled hair or wearing flowers as accessories. It had also called for heel height to be two to four inches and for makeup to be "worn at all times" and "regularly reapplied," with a minimum of lipstick, mascara and eye shadow.

What about in the US? Can a US employer require female employees to wear heels and makeup?

The EEOC focuses more on the religious and ethnic aspects of a dress code than gender aspects. Their official guidance is:

In general, an employer may establish a dress code which applies to all employees or employees within certain job categories. However, there are a few possible exceptions.

While an employer may require all workers to follow a uniform dress code even if the dress code conflicts with some workers' ethnic beliefs or practices, a dress code must not treat some employees less favorably because of their national origin. For example, a dress code that prohibits certain kinds of ethnic dress, such as traditional African or East Indian attire, but otherwise permits casual dress would treat some employees less favorably because of their national origin.

Moreover, if the dress code conflicts with an employee's religious practices and the employee requests an accommodation, the employer must modify the dress code or permit an exception to the dress code unless doing so would result in undue hardship.

Abercrombie and Fitch found out about this the hard way when they refused to hire a young Muslim woman because her hijab violated their "look" policy. (They have since changed their policy). There have been a couple of recent lawsuits regarding Transgender employees and dress codes, but just how far you can go with gender dress codes isn't quite clear.

The EEOC is clear that standards can be different for men and women as long as it's generally consistent. That is, you can require everyone to wear business attire and be properly groomed, but can require men to have short hair while women can wear long hair. That's not considered discriminatory.

So, what about high heels? Can you require them for regular business positions? Most likely yes, but should you? No.

Why not? Because it's not necessary to do a good job. Stop and think about women in business and government. Do you know if they wear heels? If your answer is "I have no clue," then that demonstrates how unimportant this is. The question is, does this employee look professional.

Require professional dress (if that's your dress code). Closed toed shoes may make sense if there are safety concerns. Otherwise, there are so many more important things to worry about than how high a woman's heel is.