Passengers will soon be able to use their mobile phones to buy train tickets,

The Association of Train Operating Companies (ATOC) has adopted a nationwide standard for rail ticketing, so that all companies can use the same system. Currently trials are being run with Chiltern Railway, National Express and the Heathrow Express. It is hoped that other rail companies will be adopting the technology.

The application, will work on 90 per cent of mobile phones that have a colour screen, even many that are up to seven years old.

To use the service the first time, people have to get the application by sending a text to a central number. The traveller then receives a text back with the application. Once this has been downloaded and installed the user can use it to send train times and routes for tickets they want to buy. Payment is by credit or debit card over an encrypted connection.

Once payment has been accepted, another text message is sent with the barcoded ticket; this can then be scanned by the train conductor and at the barriers.

Once the first payment has been made, people will only be asked to give the last three digits of their cards security code -the CV2 code.

Ben Whitaker, the chief operating officer of mobile phone applications company Masabi, which is working with Atoc to create the service, said: “The new barcode contains enough information and security for people to buy them immediately before travel and step right into the train.

“The application sits on your phone. You enter Station A to Station B, say that you have a rail card and so on. It's just like a ticket machine in your pocket."