Due to a problem under investigation between Alexandra Palace and Potters Bar trains are having to run at a reduced speed on all lines.
Disruption is expected until 18:30.
Check before you travel:
You can check your journey using the National Rail Enquiries real-time Journey Planner
Twitter:
If you would like to follow this incident on Twitter, please use #PottersBar
Compensation:
You may be entitled to compensation if you experience a delay in completing your journey today. Please keep your train ticket and make a note of your journey, as both will be required to support any claim.
Feedback:
We want to make information better - tell us how! Fill out this online Disruption Survey.