A pilot scheme has been launched by both Twitter and Transport for London to notify travellers about severe delays to train and Tube services.

Customers can opt in to receive instant notifications when there are delays to services. That way they can find alternative routes before heading into the London Underground system or to train stations.

Followers of the London Overground, TfL Rail, Central Line or District Line Twitter accounts can have the notifications set-up so they are informed directly on their mobile phones whenever an incident has occurred. They can also be sent to a computer, free as charge.

To opt in, just head to tfl.goc.uk/twitter-alerts and select the lines that are relevant to you. Some of the lines and accounts are still to be activated, which will possibly happen once the pilot scheme has ended and is judged successful.

TfL is gathering feedback from customers throughout the summer to see if the scheme should be extended.

"Like every Londoner, I rely on public transport to get me around and this world-first service looks set to become an essential tool for millions of Tube passengers," said Sadiq Khan, the recently-elected mayor of London.

"It is an innovative way of providing people with live updates from the Underground and contributes to my goal of making it as easy as possible to get around the capital."