The Celebration Bus
Time Out says
This is a tour bus with a twist, as each trip is catered especially to your group. The Celebration Bus will collect and drop you off at your bar of choice and in between take you on a guided tour of London, with complimentary drinks, karaoke and access to the bus's Spotify account onboard. Areas served are Oxford Circus, Leicester Square, Soho, Covent Garden or Trafalgar Square.