From 1 November, travellers on the London Underground will be able to access Wi-Fi internet from their smart phones or laptops as part of a six-month trial.
Wi-Fi access will be provided by BT Openzone at Charing Cross Tube station, with plans for a wider roll-out by the London Olympics in 2012, if the pilot is successful.
Earlier this year, Mayor of London Boris Johnson revealed his support for wi-fi coverage across the whole city, including on the London Underground, by the Olympics.
Around 68,000 passenger journeys a day are made at Charing Cross. The BT Openzone hotspot will be available in the ticket hall area of the station, and on the Northern and Bakerloo line platforms - but not on the tube trains. Nine London overground stations, including Charing Cross overground and Liverpool Street, already have access to BT Openzone.
According to the Financial Times, BT's Wi-Fi deployment will be relatively cheap as it will 'piggy-back' on an existing, private wireless network used by Transport for London employees.
TfL will provide travel information via the wi-fi for free. However, customers will have to subscribe to BT Openzone to access other services.
The trial is being wholly by BT, and any BT Openzone customers and BT broadband customers with unlimited BT FON Wi-Fi minutes will be able to use the service for free. Customers with O2, Tesco Mobile, Vodafone and Orange, who also have BT Openzone minutes included in their contracts can also use the service. Other users would have to buy a BT Openzone voucher online.
Kulveer Ranger, the Mayor of London's Transport Adviser, said: "An ever-growing commuter populous has been clamouring to be able to check their emails and browse the net whilst on the go.
"This is an important step towards seeing how this could be achieved and is part of the Mayor's ambition to examine ways in which we can use technology to adapt the city's transport system to meet the needs of those using it."