Nicola Thorp says the rule is unfair and outdated
A petition calling for a change to British dress code laws is to be considered for a debate in parliament there.
London receptionist Nicola Thorp, who says she was sent home from work after refusing to wear high heels, has received more than 100,000 signatures.
Under UK petition rules, any petition which receives 100,000 signatures will be considered for debate in parliament.
However, only British citizens or UK residents can sign it.
The 27-year-old says she arrived at a finance company to be told she had to wear shoes with a "2in to 4in heel" while working on reception.
When she refused and complained that male colleagues were not asked to do the same, she says she was sent home without pay.
"I'd arrived in flat, black shoes and they said 'we're going to give you a uniform', and as I was getting changed she said to me 'You can't wear those shoes'", she told the BBC.
"They said if you want to go out now and buy a pair of heels they were happy for you to do that - with my own money - and I refused on principal".
"It was a nine hour shift to escort clients from the front desk to meeting rooms, I'd be on my feet for nine hours".
The petition says: "It's still legal in the UK for a company to require female members of staff to wear high heels at work against their will".
"Dress code laws should be changed so that women have the option to wear flat formal shoes at work, if they wish. Current formal work dress codes are out-dated and sexist".