Although not VAT cases themselves, one of the main questions was whether taxi operators like Uber and Free Now are required to act as principal when entering into a contractual obligation with the passenger to provide a journey. The High Court held in the ULL case that to comply with the provisions of the Private Hire Vehicles (London) Act 1998, ULL and Free Now would have to accept a contractual obligation to the passenger as a principal to carry out the booking; if it did not, it was in breach of its licence for regulatory purposes.
Source: ey.com