A warning of increased disruption to rail services covering Gatwick over Christmas and new year has been issued.
The alert came as passengers trying to get to and from the airport were urged to allow extra time for their journeys due to the latest in a series of crippling strikes on the Southern rail network.
Services to and from the airport face disruption due to the three-day walkout by train conductors which started at midnight.
The action by members of the RMT union will be compounded by an overtime ban by members of the Aslef train drivers union, to be followed by strikes on December 13.
Gatwick Express services are among those affected by strikes also planned for December 16, 19-20, December 31-January 2 and January 9-14.
Southern said: “Due to the industrial action by drivers in the Aslef and RMT unions, regrettably we expect Southern services to be severely disrupted on every day from Tuesday 6 December until further notice.
“Services are expected to be particularly disrupted on the drivers’ strike dates with no services on most routes. There is also likely to be increased disruption over the Christmas and New Year period.
“Other operators’ services are not affected, but may be busier. Journey planners will only be updated 24 hours before the date in question, please recheck your journey before setting off.”
Gatwick said: “The strike will have an impact on Southern services, with reduced and modified services and many routes not operating. We recommend that you plan your journey in advance and allow plenty of extra time to get to the airport.
“Gatwick Express services will also be impacted during this period. Thameslink services are unaffected by the strike. Thameslink, Southern and Gatwick Express will be accepting each others tickets during the strike.”