One in five black cabs has been taken off London's roads since June due to a lack of passengers during the coronavirus pandemic, research reveals.
The number of vehicles fell from 18,900 on 7 June to 15,000 on 8 November, Transport for London (TfL) data shows.
Black cab rental firms have had to hire fields and car parks to store vehicles handed back by drivers.
The Licensed Taxi Drivers' Association (LTDA) says only 20% of drivers still have their vehicles in the capital.
General secretary Steve McNamara said London cabbies were earning "starvation wages", at around a quarter of normal levels.
Drivers "are doing desperate things" such as selling their taxis for well below market value to "get through the next few months", he added.
Many have received "no income at all" since March, Mr McNamara said.
"We're in a position now where London could lose this icon," he said. "We're a very viable business. We're an integral part of this city's DNA."
London cabbie Andy Biggs, 63, said demand had "evaporated" and he was lucky if he had three customers a day.
"When we first went back after the initial lockdown, things started to get a little bit better very slowly," he said. "But now it's as dead as it's ever been."
LTDA figures show drivers arriving at Heathrow Airport last month waited an average of nine hours before being dispatched to pick up a passenger.
Howard Taylor, 60, who has been a cab driver in the capital for more than three decades, said he went to work with "no expectation at all" of being hailed for a ride.
"I've never seen London like it. In 33 years I've never seen it as quiet, as desolate and depressing."
North London-based rental company GB Taxi Services has seen the occupation rate of its fleet of 100 black cabs drop from 95% before the crisis to just 10%.
It is one of two firms using an area of farmland in Epping Forest, Essex, to store about 220 unwanted taxis so they can stop paying to insure them.
Another rental firm, Sherbet London, has hired a car park to store 400 cabs, representing two-thirds of its fleet.
Chief executive Asher Moses said: "The whole trade has suffered. There must be 2,000 taxis on fields at the moment."
TfL said it had provided drivers with "practical advice on a number of issues" during the crisis, and added that black cabs "remain an integral part of the transport network".