Trespassers on a railway line have led to disruption across train services in Hertfordshire, Essex, Cambridgeshire and London.
Greater Anglia said there had been a trespassing incident on the line between Broxbourne and Sawbridgeworth in Hertfordshire.
Services between Liverpool Street and Hertford East, Stansted Airport and Cambridge are all affected.
Police and Network Rail staff are en route and disruption is expected until further notice, Greater Anglia said.
