Forget terrorists, forget climate change, or anything else that has been keeping you awake at night, instead worry about who or what your smartphone might be talking to if you leave it on when you go to sleep - and no, that doesn't mean the NSA, it already knows all about you.

Although it might be a little far-fetched to imagine your phone is out to get you - at least the phone itself - it might not be beyond the realms of science fiction for a computer to have designs on your life.

Last week, Stephen Hawking, one of the world's leading theoretical scientists, cautioned that thinking machines that can match or surpass humans could pose a threat to our existence.

Speaking to the BBC, he said: "The development of full artificial intelligence could spell the end of the human race."

Hawking is not the only one to have rung this alarm bell. Addressing students at the Massachusetts Institute of Technology at the end of October, Tesla chief executive Elon Musk said: "I think we should be very careful about artificial intelligence. If I were to guess, like, what our biggest existential threat is, it's probably that."

Artificial intelligence already exists of course; we encounter it in our daily lives in various forms, for instance the targeted services companies such as Amazon, Apple and Google. The popularity of such "intelligent" products and services shows people aren't too concerned about such action going on behind what they see so long as it brings convenience, and the danger here is probably how such "smart profiling" is used rather than the power of the computing itself.