Groupe Eurotunnel has signed a 10-year agreement with the British telecom firms EE and Vodafone to offer mobile services in the Channel Tunnel that links Britain and France.
With this agreement, Eurostar and Le Shuttle passengers travelling through the Eurotunnel will be able to make and receive mobile phone calls starting March 2014.
The telecom firms intend to offer 4G data services throughout the tunnel in the near future.
Eurotunnel and its partners have carried out technical work in an effort to provide these services, which are claimed to be first wireless service below sea level of 100m.
Last year, Eurotunnel signed agreements with the French mobile operators, Bouygues Telecom, Orange and SFR for installation of GSM-P services in the South Running Tunnel.
The move is part of Eurotunnel's plan to continually improve customer service due to rising demand for connectivity on the move.
According to UK-based mobile coverage solutions provider Axell Wireless, consumer mobile services in the Eurotunnel will operate on a separate system to the GSM-R specialist railway communications network that is being enabled using its wireless technology.
The company is using a fibre optic Distributed Antenna System (DAS) to transmit mobile voice and data signals throughout the tunnel.
Axell Wireless CEO Ian Brown said: "Cellular connections in rail transportation are the future, while wireless coverage is the fourth utility, people expect it as a given, wherever they are."
About 20 million passengers travel through the world's longest undersea tunnel every year. EE was formed after the merger of Orange and T-Mobile in the UK.
Image: Channel Tunnel is a 31.4 mile rail tunnel linking Kent in the UK with Coquelles in northern France. Photo: courtesy of Wikimedia commons under Creative Commons Attribution 2.5 Generic license.