A self-driving car has had its first trials on major London roads, proving the technology works – or it does with an attentive driver behind the wheel to slam on the brakes. Guided by five radars, four lasers and 12 cameras, a converted electric Nissan Leaf has been following a carefully mapped route around Beckton, in east London, driving itself along the A13 dual carriageway, around urban streets and navigating roundabouts – a particular challenge