From today, users of the Jubilee Line at and between Westminster and Canning Town stations will be able to use their mobile phone throughout their journey.
Of course, there may not be many people travelling right now due to the Coronavirus, but those who have no choice will at least be able to keep abreast of the latest news and developments even when in the tube tunnels.
Geoff Marshall has been along to try it out with TfL, so watch the video below to find out more.
The service will work with all of the UK networks and MVNOs, and the service will work on the Jubilee Line trains as well as within the stations that are part of the first public roll out.
Wi-Fi will continue to be offered within stations and platforms, with the 4G service complementing it.
More info: Wired
EDIT: Story edited to reflect the fact that the service is in fact open today to the public and not tomorrow, as originally written.