Commuters in London could soon benefit from 4G connectivity while travelling on the Tube.
Transport for London (TfL) has confirmed it is looking for a supplier to build a 4G-capable network across the London Underground.
The procurement process is set to get underway after next week's general election.
Passengers on the Tube can already use a Wi-Fi service, which was introduced ahead of the London Olympic Games five years ago.
However, TfL now wants to ascertain if it is "commercially viable" to go further by offering a 4G system.
A TfL spokesperson said: "We are keen to offer full mobile phone coverage for our customers.
The representative added that any moves to deliver 4G on the Tube would "follow engagement with staff and customers".