Scotland and London will soon start testing self-driving vehicles as part of a £25m funding awarded by the UK government for the project, which aims to be operational in 2021.

Driverless buses will ferry passengers across Scotland's Forth Bridge, on a a 14-mile route between Fife and Edinburgh.

Addison Lee and Jaguar Land Rover will lead two separate trials of driverless taxis in London before launching public services, by 2021.

The Scottish driverless bus service will use five buses, carrying up to 42 passengers. The vehicles will be converted from manually driven to autonomous vehicles by Fusion Processing, a technology company which specializes in sensors and control systems.

In London, a consortium led by Addison Lee Group and also includes Oxbotica, DG Cities, Nominet and Immense Simulations, will roll out four AV pilots using 15 autonomous vehicles. Designed to complement existing public transport, the service will be app-based, on demand and based on ride-sharing. The vehicles will be low-emission, designed with the pedestrian in mind and priced at a level to generate demand without impacting other public transport. The companies aim to have driverless taxis capable of going anywhere in the borough and available for public hire by 2021.

As the UKs leading self-driving vehicle software company, Oxbotica’s technology will underpin the consortium, while DG Cities will provide the urban blueprint for the scheme. Immense Simulations will take the data from the pilot and model impact on other London boroughs and other UK cities and Nominet will provide cyber-security expertise to the platform.

Jaguar Land Rover will also launch a "premium mobility service" in parts of the capital, using six autonomous Land Rover Discovery cars.

The companies will share £25m in state funding from the UK government.

The UK established a center for connected autonomous vehicles in 2015, with £250m of government investment.

A limited numbers of autonomous cars have also been tested on the roads, but with drivers behind the wheel in case of emergency.

Japan is also planning to have a fleet of driverless taxis ready for service in Tokyo for the 2020 Olympics.

In the U.S., the first fully autonomous service is expected to arrive in Phoenix, Arizona, where the Google's Waymo plans to start operating driverless taxis as soon as December.