Commuters will be able to use phones throughout the network

London Underground had hoped to make mobile coverage available on the Tube from mid-2008 but introducing it has been more difficult than expected.

On Wednesday LU revealed mobile phone and new technology coverage would not be extended across the Tube network until at least mid-2009.

But mobile phone coverage will be trialled at Bank and Waterloo stations for six months from April 2008.

Coverage will be available on the Waterloo & City platforms and will extend to tunnels between the two stations.

LU's Richard Parry said: "The below-ground sections of the Underground (accounting for 45% of the network) are one of the few places in London where you are unable to use a mobile phone.

"We recognise that there is now growing demand for mobile coverage to be extended to deep-level sections of the Tube."

He said the main aim of the trial is to decide "whether it is technically and commercially viable for coverage to be extended across the Tube network".

Bomb fears

He added that if the trial is a success then LU will consider how to provide mobile phone and telecommunications services across the network.

Plans to have mobile phone transmitters in the Tube were first unveiled in March 2005.

But there were fears it might provide a new method of detonating terror blasts following the 7 July attacks on three Tube trains and a bus, because the March 2004 train bombers in Madrid used mobile phones.

Fears were allayed when it was revealed that they detonated the bombs by the phones' timer functions, not a signal, and that any risk was minimal.