Trains are delayed this morning (November 6) due to a track safety inspection taking place between New Barnet and Potters Bar.
Services are still able to call at all stations, except for Hadley Wood and New Barnet, but Great Northern are warning customers to "allow up to an extra 20 minutes" for their journey.
For those travelling from London towards Hertfordshire, trains are running as normal.
"A safety inspection of the track is currently taking place between New Barnet and Potters Bar," read an update from Great Northern.
"Trains are currently running at a reduced speed and are unable to call at Hadley Wood or New Barnett in the direction towards London.
"If you wish to alight at these stations, please continue to Oakleigh Park and change there for a service back towards Welwyn Garden City where trains are able to stop as normal.
"Your journey time will be extended if you require these stations and we ask that you allow up to an extra 20 minutes to complete your journey if you are travelling towards London.
"If you are travelling form London towards Welwyn Garden City, trains are able to call at all planned stations as normal in this direction."
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