Police were called to a track a short distance from Erith station today (March 24) at 8.15am to reports of a casualty.
Emergency services arrived, but the person was pronounced dead at the scene.
An investigation is taking place to establish the circumstances leading to the death.
The incident has caused major disruption on both Southeastern and Thameslink services, with trains currently unable to run on the Woolwich line.
There are delays between Dartford and London Cannon Street on the Southeastern, and between Rainham in Kent and West Hampstead Thameslink and Luton on the Thameslink.
National Rail estimates that major disruption will last until 1pm, but this may last even longer.
Thameslink says there is no estimate on when the line will reopen between Dartford and London Bridge.
A British Transport Police spokesperson said: “We were called to an area of the line close to Erith station at around 8.15am today, Monday, following reports of a casualty on the tracks.
“Officers attended along with paramedics but sadly a person was pronounced dead at the scene.
“Enquiries are ongoing to establish the circumstances leading up to their death.”
If you feel affected by what has happened and wish to find support, you can contact the Samaritans on 116 123 via phone for a confidential chat or email jo@samaritans.org.
