Rail passengers are being advised not to travel unless necessary after heavy rain flooded part of the Norwich to London mainline.
The track at Manor Park near Stratford in London is currently under water, which means major delays on most services into and out of London Liverpool Street.
Many trains are being cancelled and there are no services between Chelmsford and London.
It is affecting all services on the Norwich, Clacton and Southend lines. Disruption is expected to continue till at least 10am.
Passengers are advised to check with Abellio Greater Anglia here before they travel.
Southern has also cancelled trains between Clapham Junction and Milton Keynes.