Uber drove its revenue up by 61 per cent last year but warned an ongoing court battle over the employment status of its drivers could hurt its future finances.
The private hire firm, which claims its drivers are self-employed, is fighting against an Employment Appeal Tribunal decision that drivers should be classed as workers with minimum wage rights.
The company's UK revenue jumped by 61 per cent to £59.5m last year from £36.9m in 2016, despite facing legal and regulatory battles across the country.
Pre-tax profits also rose 53 per cent to £4.6m, accounts for its UK business revealed.
Last year TfL refused to renew Uber's licence to operate in the city on passenger safety grounds, but the ruling was overturned in June.
It was also hit with suspensions in other cities, including Sheffield.
In its accounts, the company warned a number of potential changes to the industry could have a “negative effect” on its future financial position and cash flows.
It said it was “exposed” to legal and regulatory risks as well as claims and litigation related to Uber's classification of drivers as independent contractors.
The company added that its business model was under threat from the “interpretation and enforcement” of existing regulations.
An Uber spokesperson said: "We continue to invest in expanding across the UK with more than five million riders and 60,000 licensed drivers now using our app.
"Over the last year we’ve introduced a number of improvements for both passengers and drivers, from 24/7 telephone support to free sickness, injury, maternity and paternity protections."