Thameslink train lines are blocked between St Albans and London. Picture: Govia Thameslink (Image: www.peteralvey.com)
Trains are unable to run between St Albans and London St Pancras due to a problem with the overhead wires.
A safety inspection is currently under way on the track between West Hampstead Thameslink and St Pancras, with no trains running in either direction.
Travellers are currently being advised to delay their journey or not travel at all, as major disruption is expected until 10pm tonight.
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