How young is too young to own a smartphone?

A Spanish company believes seven-year-olds would be safe if they used a mobile it has developed and put on show at the Mobile World Congress trade expo in Barcelona.

The special version of Android involved is designed to be tied to the device, meaning youngsters cannot bypass its protections.

Escudo Web is now seeking a hardware partner, as it explained to the BBC's technology correspondent Rory Cellan-Jones at the event.