Wallpaper that blocks Wi-Fi signals but allows mobile phone signals through has been developed by scientists from the Institut Polytechnique Grenoble INP and the Centre Technique du Papier.

Anti Wi-Fi blocking Wallpaper Wireless Network Institut Polytechnique Grenoble INP Centre Technique du Papier

The silver crystals embedded within the material are arranged to specifically block the wireless frequencies uses by internet routers so your signal cannot be accessed by those outside the walls.

The work appears to be based on a PHD thesis prepared by Viva M. Fabien de Barros in the 2010-2011 academic year, under the joint direction of M.Tan Phu Vuong and Pierre Lemaitre-Auger at the Institut Polytechnique Grenoble INP.

"This work aims to develop a new means of protection against electromagnetic waves. More specifically, the study focuses on a technology capable of filtering only Wi-Fi and GSM waves across large areas of a dwelling, such as a wall. To do this, the wallpaper, has been studied," the PHD filing states.

The research applied 'frequency selective surfaces' to paper, using conductive ink.

"The simulation results show that, once on paper, they are able to filter two or three bands at levels in excess of 20dB."

The Wi-Fi-blocking paper could be available in shops next year and is expected to go on sale for the same price as existing mid-range wallpaper.

That would make it a lot cheaper than a similar British system developed back in 2004 that blocked Wi-Fi signals while still letting through mobile phone and emergency service calls. A square metre of that material cost about £500.

One slight problem with the wallpaper system is that rooms with windows will still allow your signal to be accessed outside.

To combat this, the scientists are now working on version of the same technology that uses a clear coating with the same blocking qualities.