New York gets mobile phone coverage underground

New Yorkers can use their mobile phones on the subway now as the city's antiquated transport system finally enters the hi-tech era.

A pilot scheme started today at four stations in Manhattan. The plan is to extend phone coverage underground to all 277 stations by 2016.

The network, which is more than a century old, carries more than four million passengers around the Big Apple every day.

The subway used to be the one place in New York where there was no mobile phone coverage but now there is no respite.

The BBC's Laura Trevelyan spent the day below ground to find out more.