Gatwick urged passengers due to fly today to leave extra time for their journey to the airport following chaos on the railways on Thursday.
Commuters complained of being “sardined” into overcrowded trains, while others missed flights from Gatwick.
While some lines have reopened, travellers planning to use Gatwick Express and Southern services have been advised not to travel via London Victoria station.
National Rail said disruption would last until at least 10am.
In an update at 6am this morning, Gatwick said: “Due to a loss of signalling power yesterday, train services are severely disrupted on the London Victoria line. Please check your route in advance and allow extra time.”
John Halsall, managing director of Network Rail’s South East route, “sincerely apologised” for yesterday’s disruption on routes into London Victoria.
He admitted to the BBC that the company had failed in its job to provide “a reliable railway for train operators and the travelling public”.
Victoria is the UK’s second busiest station used by about 210,000 passengers a day.