Google Duplex impressed and scared the world in equal parts when it was unveiled, and now we've seen how a conversation goes with another chatbot.

Duplex, for a quick primer, is Google's AI-powered voice bot which can call businesses on a person's behalf for things such as booking hair appointments. It's so realistic that everyone has decided that bots must declare themselves as such before chatting with a human.

A company known as PolyAI – which specialises in...