All trains through Colchester station have been blocked after a trespassing incident was reported on the tracks.
Shortly before 4pm, Greater Anglia warned commuters that all mainline services through Colchester would be disrupted until further notice.
The firm said on Twitter: "Due to a trespass incident at Colchester all lines are blocked.
"Train services running through this station may be delayed.
"Disruption is expected until further notice."
The incident comes after multiple Greater Anglia services to and from London were cancelled this morning.
Commuters were advised to avoid travelling to the capital by rail after damage to overhead wires between Colchester and Marks Tey.
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