The move to get mobile phones working on the tube moved a step closer as BT announced wi-fi trials at Charing Cross underground station.
The six month trial will bring wi-fi connectivity to the ticket hall and both the Bakerloo and Northern line platforms.
It will be free for BT broadband customers and for mobile users with free wi-fi minutes.
Mayor of London Boris Johnson wants to see widespread mobile coverage.
The Charing Cross trial begins on 1 November.
Kulveer Ranger, the Mayor of London's Transport advisor welcomed it.
"An ever growing commuter populace has been clamouring to be able to check their e-mails 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 the way in which we can use technology to adapt the city's transport system to meet the need of those using it," he said.
Boris Johnson has pledged to make London a huge wi-fi hotspot in time for the 2012 Olympics.
More than half of London's councils have signed up for the scheme - known as Project Wi-fi.
Mr Johnson wants to see lamp posts and bus stops wi-fi enabled.
The City of London already has 95% wi-fi coverage.