Faults with the first trains to head out on the Metro system are causing delays for passengers this morning.
Customers have been urged to leave extra time for their journey after the issues came to light.
A spokesman for Metro said: "We currently have delays system wide due to an earlier train fault with the first trains.
"Please leave extra time for your journey where possible.
"Metro apologise for the disruption to your journey."
The service went on to add that passengers can find its refund policy on its website, which gives a guide on how to ask for refund for any journey delayed by over 15 minutes from the advertised timetable.