Speaking to Sky News, the shadow home secretary backed the decision not to renew the taxi-hailing company's licence in London.
Uber has 21 days to appeal and can continue to operate until that process expires.
The agency said the factors it considered included Uber's "approach to reporting serious criminal offences" and its use of software created to evade the authorities.
"They have a lot more scrutiny on them now", said Reed Galen, a political consultant who worked with Uber on a campaign in Austin.
Transport for London (TfL) yesterday informed Uber London Limited (Uber) that it will not be issued with a private hire operator licence after expiry of its current licence on 30 September. "But that requires a dialogue we sadly haven't been able to have recently".
Dear London: we r far from ideal but we have 40k licensed drivers and 3.5mm Londoners depending on us.
Its arrival in the capital in 2012 was controversial because it significantly undercut the prices of the city's famous black cab fleet, one of the most expensive in the world. "But as Uber's problems worsen, regulators feel emboldened to proceed and rightly sense that it's particularly urgent for them to do so". And its 40,000 drivers in London will be allowed on the roads until all the options for appeal have been exhausted.
So what were Uber's crimes which made them "unfit" for a license? The sudden rejection has affected 40,000 Uber drivers in the UK.
What's more, the public is concerned about the many safety issues posed by Uber drivers, with many not trusting the company's background checks of its partners. The city of London just revoked Uber's licence to operate in the city.
Travis Kalanick, co-founder and CEO of Uber, speaks during the opening of the Digital Life Design (DLD) Conference in Munich, Germany in 2015.
Jacob Kirkegaard, a senior fellow at the Peterson Institute for International Economics, told me there are also concerns that the software could be used to shield the company from being tracked by the city for its compliance with labor laws, such as how many hours drivers are operating on a daily basis.
"Of course Uber need to meet safety standards, but Labour always take it too far and simply don't have the balanced approach the country needs at this time".
The ride sharing company has initiated an online petition, "Save Your Uber in London", on the Change.org website following the TfL decision, which received nearly 600,000 signatures by Saturday evening. "The black cab is an iconic part of London".