Uber Technologies (UBER) and Wayve unveiled supervised autonomous rides in London, marking the beginning of self-driving trips in the United Kingdom.

Starting Wednesday, Londoners requesting an UberX, Uber Electric, or Uber Comfort may be matched with a Wayve ride at no extra cost, with upfront fares shown in-app, according to a statement from the two companies.

Riders will travel in an all-electric Ford Mustang Mach-E equipped with the Wayve AI Driver and surround sensors, per the statement. The in-vehicle experience, designed by Uber, features interactive screens available in 64 languages where riders can start their trip and view the vehicle's planned path.

The companies said a small number of vehicles are being introduced in the initial phase and plan to grow numbers in line with "demand, readiness, and regulation."