Some US tech firms have gained a reputation for being willing to launch products before it is clear whether they could be damaging to society.

But Microsoft's president, Brad Smith, says that it is not good enough for such companies to absolve themselves of responsibility and say that it is solely up to lawmakers to decide what is right and wrong.

Mr Smith's book - Tools and Weapons: The Promise and the Peril of the Digital Age - aims to serve as a wake-up call to the industry.

He spoke to the BBC's Leo Kelion while visiting London.