Transport for London are under severe pressure to act following the arrival of Taxify in the capital.
The taxi and private hire regulator has said they are "urgently" investigating the Estonian start up following questions surrounding their legality in London.
According to London publication City AM, a TfL spokesperson said "Taxify is not a London licenced private hire operator. We are urgently investigating the nature and extent of its activities and will take action where appropriate."
It is thought that Taxify have purchased an existing private hire operators licence and changed its business model without notifying TfL. There is concerns regarding the use of the name Taxify given no taxis are on its platform.