Sufferers say the electro-magnetic waves emitted by wireless computer networks - wi-fi - leave them feeling exhausted, nauseous and sleepless.

Author Kate Figes, spent hundreds of pounds installing wireless internet in her Stoke Newington home, then found it made her so ill she had to scrap it.

Ms Figes, 49, claims she is so sensitive to wi-fi's electro-magnetic waves she can instantly tell whether it is installed in a particular room.

This comes days after campaigners called for parents to remove the system from their homes to prevent harming their children's health.

Ms Figes said: "The day we installed wi-fi two years ago was the day I started to feel ill. At first I could not work out what the problem was. I had no idea why I felt so sick and run-down. But I knew that when I walked through the front door it felt like walking into a cloud of poison.

"Imagine being prodded all over your body by 1,000 fingers. That is what I felt when I walked into the house... Then I started to think it might be the wi-fi, so we scrapped it - and I felt better."

She added: "Most people I've spoken are really dismissive, but I don't think they've considered the long-term impact of this technology." The mother-of-two is just one of many people who contacted campaigning group ElectroSensitivityUK about their fears over the harmful effects of wi-fi.

A spokesman for the group said: "We've been inundated by calls from people who know this is affecting them, but in many cases are wary of speaking out. The telecommunications companies pour scorn, but none of them has been able to prove wi-fi is safe."