Gatwick Express services will not run until January 2. Network Rail will undertake vital improvement work at three locations on the network: replacing a major rail junction near Purley (north of Gatwick), upgrading signalling at Victoria and working on a new platform at Gatwick Airport station.
Southern, which operates operates Gatwick Express, will run a revised train and bus replacement service between London and Gatwick Airport between December 26 and January 1. Details of the revised services on this link.
Information on the Gatwick Express website:
Due to a major signalling problem caused by a cable fire near Brighton, Gatwick Express services will continue to operate between London Victoria and Gatwick, but will be extended to Three Bridges tonight.
On Saturday 22 December, Gatwick Express services will run between London Victoria and Gatwick Airport, stopping additionally at East Croydon in both directions on services between 0700-2100.