Uber is being sued for over $300 million by thousands of London's iconic black cab drivers

• Uber is being sued by thousands of London cab drivers over claims it operated illegally.
• The suit could ultimately be worth over £250 million ($313 million) law firm Mishcon de Reya said.
• Uber has dismissed the claims made in the lawsuit as "completely unfounded."

Over 10,000 London taxi drivers are suing Uber for £250 million ($313 million), the legal firm Mishcon de Reya announced.