Addison Lee has suspended one of its drivers following reports a gay couple were thrown out of a taxi because they were holding hands.
The driver, who picked up the men from G.A.Y in Soho, London, last night, has also being accused of calling the couple "dirty".
The passenger, who used the Twitter handle @LK_today, tweeted: "Just been ejected from an @AddisonLeeCabs taxi for being gay. Thanks for the homophobic treatment.
"My BF and I got into a taxi from G-A-Y Late. Started holding hands and were told to get out, and called dirty.
"Thank you to everyone for your messages of support, they mean a lot. We're home now, after a very nice black taxi journey."
Addison Lee, who are London's biggest taxi firm, responded to the incident by saying it would be "investigated thoroughly."
Meanwhile, cab users responded furiously on Twitter, with many claiming they would no longer be using the company.
So it seems I'm going to be finding another cab firm now - it's all over now @AddisonLeeCabs. A hateful driver - fire him, then charge him.— Merrington (@merr1ngton) August 22, 2013
Some users demanded that unless the cab company revoked the driver's licenses they would be turning to other firms.
Ash Auger branded the treatment "disgusting," while Emperor von Bears said she hope something "would be done" about the treatment.
A statement from the firm read: “We are aware of an incident involving an Addison Lee vehicle in London last night.
"This incident is being investigated thoroughly, and the driver has been suspended from duty while the investigation takes place.
"We are also in contact with the customer to understand more about what happened.
"Addison Lee does not tolerate any form of discrimination. We pride ourselves in delivering the highest possible level of professional service, and we take matters like this very seriously."