Vulnerable people must be protected from robots, a top robotics expert has warned. Noel Sharkey, of the University of Sheffield, has called for international guidelines to be set for the ethical and safe application of robots before it is too late. Writing in the journal Science, he said that as the use of robots increased, decisions about their application would be left to the military, industry and parents, instead of international legislative bodies. He cited research into service robots that demonstrated close bonding and attachment by children, who, in most cases, preferred a robot to a teddy bear. However, while short-term exposure could be enjoyable, no one has yet quantified the psychological impact on children who could end up being left with "robot minders" for many hours a day.