Tube passengers will be able to make mobile calls in some Underground tunnels for the first time today.

A trial was launched offering 4G signals on the eastern section of the Jubilee line, between Westminster and Canning Town.

Transport for London aims introduce 4G across the entire line by the end of the year – with other Tube lines following.

The project means 4G will soon be available in all Jubilee line tunnels and platforms – starting to tackle the capital’s biggest “not spot”, where there is no reception for conventional voice calls across the deep-level Underground.

Customers of all four UK mobile network operators – EE, O2, Vodafone and 3 – will be able to access the system.

There will also be “enhanced” wifi connections at stations, replacing the Virgin Media deal that is coming to an end.

Connections for super-fast 5G have also been laid in the tunnels, as well as the Home Office’s Emergency Services Network (ESN) radio link.

TfL, which has paid £10m towards the 4G infrastructure, hopes to receive £25m in revenue over the first five years.

It is aiming for a “long-term revenue stream” that lasts 20 years, with the option of a further five to make a total of 25. Yesterday it predicted up to £500m in lost Tube and bus fares as a result of the coronavirus crisis.

The 4G signal will provide passengers with uninterrupted connections – allowing them to watch a video, download emails and view social media.

Ticket halls and corridors within stations are also covered by the pilot, except for London Bridge and Waterloo stations where the signal will only be available on the Jubilee line platforms.

TfL hopes to award a contract to deliver mobile coverage across the whole Underground network in the summer, so that other lines can begin to get mobile connectivity from 2021.

TfL is currently working in 53 stations, out of a total 127 stations which require works, to install the required cabling.

Fuller details of TfL’s 4G plans were included in its most recent finance committee papers.

Heidi Alexander, deputy mayor for transport, said: “Poor mobile connectivity is a major barrier to growth so I’m delighted that Tube passengers on the eastern section of the Jubilee line will be able to enjoy 4G access.

“This milestone will enable Londoners and visitors to get online while travelling through tunnels and platforms, doing everything from watching videos and messaging friends to catching up on emails.”

Shashi Verma, chief technology officer at TfL, said: “This has been very complex work to install the necessary equipment to allow our customers to be able to get phone reception within our tunnels while keeping the stations open and operational.”

Derek McManus, chief operating officer of O2, said: “It will also mean thousands of fans travelling to The O2… will now be able to share their experiences with friends and family, before and after a show.”

An edited version of this story appears in today’s Evening Standard.