Mobile phone calls and 4G internet browsing will come to the London Underground from 2019, with the new Elizabeth Line the first to get continuous coverage between every station.
The mayor of London, Sadiq Khan, announced the news on 10 August, stating that 4G coverage will be available for passengers to use in the underground tunnels between stations.
Transport for London (TfL) began installing Wi-Fi in Tube stations in 2012, but this only provides a signal to customers on platforms, in ticket halls or on stationary trains in the station.
By introducing 4G, passengers will get continuous high-speed internet coverage both at stations and in the tunnels between them.
The new Elizabeth line, connecting Heathrow airport and Reading to Abbey Wood and Shenfield, while passing through central London, will open in December 2018 and become the first line to provide passengers with continuous 4G coverage.
A letter sent by the mayor to all 33 London local authorities said his goals for connecting the capital include "delivering 4G mobile connectivity to London Underground, both in stations and tunnels from 2019, future-proofed ready for 5G".
It is understood that tenders to deliver the mobile coverage will be sent out shortly, and the first trials are expected to take place on the two-station Waterloo & City line, which connects Waterloo railway station with Bank Tube station. These tests will take place at night and during the weekends, when the station is closed.