When it comes to booking a taxi and you don't fancy hailing one on the street, mostly you have two options:  Uber and FreeNow. David Mitchell is a taxi driver and is launching what he and his colleagues hope is a viable alternative to the big two. ‘Tap a Taxi’ drivers initially purchase their share and then pay a flat subscription per month and users pay what it says on the meter with no other fees.  It operates as a coop and the app is downloadable now.  David Mitchell joined Joe this morning.