BT's FON Wi-Fi service has signed up more than 100,000 users, expanding the provision of free wireless internet access across the country.

Subscribers to the programme share a small proportion of their domestic broadband connection through a separate, secure channel on their wireless router. These hotspots are made available at no extra cost to every other BT FON user, creating a voluntary network of shared Wi-Fi connections.

The service was launched last October. A similar scheme, allowing businesses to use part of their connection to offer free wireless access on their premises, is due to launch later this year.

“BT has been instrumental in creating Broadband Britain, and we have built on that by calling upon entire communities to come together to create a Wi-Fi network that covers the country, driven entirely by local broadband users," said Jon Hurry, director of consumer internet services at BT.