Google has announced it is to build its own driverless cars instead of modifying vehicles manufactured by other companies.

There will be no steering wheel or pedals in the vehicles, which will come equipped with a stop/go button in place of conventional controls.

Co-founder Sergey Brin revealed the company's plans at a conference in California. The cars, which will use electric power, will have a top speed limited to just 25 mph at first. 

A fleet of around 100 cars will be built by the company. Until now, the firm has used vehicles manufactured by other firms to trial its driverless technology.

Chris Urmson, director of the project to build the car, said: "We're really excited about this vehicle - it's something that will allow us to really push the capabilities of self-driving technology and understand the limitations."

He added that the technology could be used to improve people's lives through improved mobility.