A three-day strike by Southern Rail train drivers begun at midnight affecting services across the region.
Thousands of rail commuters have been told not to travel at all this week, with the strike action affecting Tuesday 10th, Wednesday 11th and Friday 13th January.
The strike by members of the ASLEF union is in a row over driver-only trains.
Southern Rail are providing 200 buses to help passengers reach other train networks.
Southern Rail Passenger Services Director, Angie Doll.
It is likely to be one of the most disruptive rail strikes in decades.
Virtually no Southern trains will run across the network.
The east of the region will be affected.
The west of the region will also be affected.
Further advice can be found at: http://www.southernrailway.com/your-journey/strike/aslef-strike/