For proof of London cabbies' devotion to their beloved black cabs, look no further than one unidentified driver's tattooed forearm. Photographed during a taxi drivers' 90-minute protest in central London on 10 February, the driver was one of some 8,000 cabbies who stopped traffic in this part of the city to protest Transport for London's acceptance of US-based on-demand ride service Uber, along with the agency's decision to ease rules related to passenger pickup — rules designed to increase rider safety, says Unite, the taxi driver's union. Cabbies also complain that an influx of Uber vehicles has heightened congestion in London and increased pollution.

Speaking to Reuters on Wednesday, chair of Unite's London and Eastern region Jim Kelly said, "The reduction in safety for passengers because of the 'light touch' regime is to be deplored. It is a race-to-the bottom, when in 2016 we want the highest possible standards."

Earlier in the week, Uber offered to allow the city's taxi drivers to use its smartphone app commission-free for a year, which would give customers the opportunity to book black cabs, similar to rival apps Hailo and Gett. The cabbies flatly rejected the peace offering, calling it a "PR stunt."

If you would like to comment on this or anything else you have seen on BBC Autos, head over to our Facebook page or message us on Twitter.

And if you liked this story, sign up for the weekly features newsletter, called “If You Only Read 6 Things This Week”. A handpicked selection of stories from BBC Autos, Future, Earth, Culture, Capital and Travel, delivered to your inbox every Friday.