The newest Wi-Fi threat to children comes from laptops, according to one expert who says wireless transmitters in mobile computers are a cause for concern.

While Wi-Fi transmitters are located in the main tower of many PCs and therefore at a safer distance, laptops are often placed on your lap and so people are within a couple of centimetres of the source of Wi-Fi emissions.

This means that children would receive exposure comparable to that of a mobile phone and should therefore keep a safe distance from the embedded antennas, according to Professor Lawrie Challis, chairman of the Mobile Telecommunications and Health Research Programme.

Professor Challis told the Daily Telegraph that if we are discouraging children from using mobiles they should also be prevented from placing Wi-Fi laptops on their laps.

Challis is also worried about the lack of investigation carried out into exposure levels and emissions from Wi-Fi networks in schools. Following such concerns, teachers have requested an investigation to see if there are any health risks from wireless computer networks in schools. The Professional Association of Teachers union (PAT) has also said that there is a lack of long-term evidence to prove the safety of Wi-Fi networks.

However, some experts argue that Wi-Fi poses a more limited threat to children than mobile phone towers, which operate at 10,000 times the power of Wi-Fi units, is still to be proven.