A Chinese telecoms firm is bidding to install mobile phone transmitters in the London Underground in time for the 2012 Olympics, it has been reported.
According to the Sunday Times, Huawei is offering to put in the £50 million phone network free of charge as a gift from one Olympic nation to another.
The paper said mobile network operators Vodafone and O2 had agreed to pick up the tab for installation work, while Huawei would hope to make an income from maintenance fees.
A Transport for London spokesman said: "Transport for London and the Mayor of London are currently in discussion with mobile phone operators and other suppliers about the potential provision of mobile phone services on the deep Tube network.
"Given the financial pressures on TfL's budgets, any solution would need to be funded through mobile operators with no cost to fare or taxpayers. Discussions are ongoing."
Conservative MP Patrick Mercer said an underground mobile network of the kind already installed in Hong Kong and Paris would be "extremely helpful" for emergency workers in the event of a terror attack.
But he warned it "absolutely answers a terrorist's prayers", by providing a means of detonating devices on the Underground.
Mr Mercer told the Sunday Times: "Whoever takes the decision has to be aware it is a double-edged sword.
"It has been proven that a proportion of the cyberattacks on this country come from China.
"I wonder when the eyes of the world are upon us whether there is sense in using a Chinese firm to install a sensitive mobile network."