CCTV cameras are already in place on Metro trains

The technology has been installed by Metro operator Nexus to cut crime and anti-social behaviour on the system.

Passengers can use mobile phones to report in confidence anything that concerns them to Metro's control room, which can then act on the information.

Posters have been displayed on all trains to show people the number they need to contact.

Text messages go to a controller based in South Gosforth, who then passes the details quickly to the Metro Police Unit and British Transport Police.

'Without fear'

Controllers can text the person back to ask for further information and to acknowledge receipt of the text.

Nexus Director General Mike Parker said: "The great advantage of being able to send a text message to our control room is the speed at which this can be done.

"It also means that incidents can be reported as they happen without the fear of being seen by those that are involved."

Nexus says it will greatly improve the chances of catching anyone who misbehaves and abuses the Metro system.

Passengers are asked to use the number only to report an incident and not to request timetable/Metro information.

In an emergency, passengers should still dial 999.