how to transfer your mobile number to three and use london underground wifi
setup a three mobile tube password then
When you’re next in a London Underground station with Wi-Fi:
Turn on Wi-Fi on your device.
Search for Virgin Media WiFi from the available connections and connect to it.
On the Virgin Media page that opens in your browser, go to the Other providers dropdown and select Three.
Enter your Three number and the password you chose, then select Register.
You’ll now be able to connect to Wi-Fi in London Underground stations. Your device will remember your details in future, so you’ll automatically connect next time you’re at a participating underground station.