Apple's chief executive Tim Cook has confirmed that the iPhone giant is working on self-driving cars for the first time.

The company has long been rumoured to be developing autonomous driving and vehicles fitted with driverless technology have even been seen around the company's California headquarters, but the notoriously secretive company has so far refused to confirm its plans.

Self-driving vehicles are seen as a major opportunity for technology companies, with Google and Uber among those developing the software.