You don't need a badge to pick up a black cab. Why would the met look for a back door into Uber when TfL can give them access to all licensed drivers' portfolios? If terrorists realised that their Pryeye only came under scrutiny if they signed for Uber after being licensed by TfL they'd simply sign for Addison Leee or any of the other 148,254 minicab firms operating in London.