BT has joined forces with the Google-backed Spanish wireless technology company Fon in a bid to persuade three million UK internet users effectively to transform their home wireless broadband networks into public hotspots.

These allow anyone with a wifienabled phone, laptop or games device to access the internet for free.

The Fon system works by splitting a user's broadband connection in two and allowing a small slice of bandwidth to be freely accessible by anyone who steps into range of the wireless transmitter . . . typically up to 50 metres in standard home networks. The reward for the BT customer is being able to share the connection of any other member of the "Fon philosophy" in 190,000 hotspots worldwide.

This is the first time Fon has teamed up with a major telco, and BT's Irish division is understood to looking into repeating the initiative. BT Group has taken a stake in Fon as part of the deal.

An Eircom spokesman said there had been internal discussions within the firm about Fon but no plans as yet. Last week it emerged a security flaw in 250,000 Motorola routers resold by Eircom made it easy for wifi jackers to piggyback on an Eircom wireless network. Eircom said it is testing a new security protocol to replace the existing standard.