Ethics guidelines are urgently needed to control the growing use of robots in caring for children and the elderly, says one UK robotics expert.

Professor Noel Sharkey, of the Department of Computer Science at the University of Sheffield, makes his case in today's issue of the journal Science.

Sharkey argues that the steady increase in the use of robots in day-to-day life poses unanticipated risks and ethical problems.

In particular he worries about the impact of long-term exposure of "vulnerable" groups such as children and the elderly to "personal care" robots.

"There are already at least 14 companies in Japan and South Korea that have developed child care robots," says Sharkey.

"The question here is, will this lead to neglect and social exclusion?"

Sharkey says studies have shown that children prefer robots to a teddy bear and develop attachment to the machines.