Tim Armitage is the director of UK Autodrive, a three-year project carrying out trials of self-driving cars in Milton Keynes.

The cars have been struggling - like the rest of us - with roundabouts, he tells Radio 5 Live's Wake up to Money.

Cities are "an ever-changing complex environment that you as a human driver take for granted," he says.

Within five years he thinks we'll see cars that can drive on the motorways or in some parts of cities, but full-blown autonomy is still a long way off.