Ford insists it will have fully autonomous cars, without steering wheels or brake pedals, on the roads by 2021.

The firm plans to use them within an Uber-like ride-sharing service at first before considering putting them on sale.

But rival car-makers have suggested that deadline is too ambitious, as Rory Cellan Jones reports from the CES tech show in Las Vegas.

Follow all our CES coverage at bbc.co.uk/ces2017