A person has died after the emergency services were called to reports of a casualty on the tracks.
The British Transport Police (BTP) and paramedics were called to the Thameslink line in Kentish Town at 6.19am this morning.
A person was pronounced dead at the scene.
The BTP say the incident is not being treated as suspicious and a file will be prepared for the coroner.
Govia Thameslink Railway warned commuters this morning travelling into London St Pancras to expect disruption due to emergency services attending an incident.
The line was shut until 7.30am.
All lines are now open through West Hampstead and St Pancras but services travelling through Hertfordshire and Barnet remain subject to delays and cancellations.
All stations currently have a severely reduced service, Thameslink says, with disruption expected until 3pm.
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