Britain is in the grip of a Wi-Fi revolution with offices, homes and classrooms going wireless - but there is concern the technology could carry health risks.
The Government insists Wi-Fi is safe, but a Panorama investigation shows that radio frequency radiation levels in some schools are up to three times the level found in the main beam of intensity from mobile phone masts.
There have been no studies on the health effects of Wi-Fi equipment, but thousands on mobile phones and masts.
The radiation Wi-Fi emits is similar to that from mobile phone masts. It is an unavoidable by-product of going wireless.
In the last 18 months another two million of us in the UK have begun using Wi-Fi.