Passengers are facing days of commuting misery as drivers on Southern Railway take industrial action.
Members of the drivers' union will strike on Tuesday, Wednesday and Friday in a dispute over driver-only trains.
The operator's owners lost a legal bid to halt the walkout, which will mean many commuters will have to work from home, take time off, or attempt to drive because of the huge disruption.
Charles Horton, chief executive of Southern's parent company Govia Thameslink Railway (GTR), confirmed there will be no services on strike days and "severe disruption" during an ongoing overtime ban.
The shutdown of Southern's services will be the worst disruption since the railways were hit by a lengthy strike by signal workers in the mid 1990s.
Transport Secretary Chris Grayling said he's "mad" about the strike.
Speaking on ITV's Good Morning Britain, he said: "I can't order them back to work, I wish I could. If I had the power to order everyone back to work today I would do it.
"I'm mad about this because this strike is based on a totally false premise.
"This is a completely spurious strike, it's based on entirely political premises."
Around 300,000 passengers travel on 2,242 Southern services every weekday, including busy commuter routes from Sussex to London Victoria.
They have suffered months of disruption because of the Aslef dispute and a separate row with the Rail, Maritime and Transport (RMT) union over changes to the role of guards, as well as staff shortages, staff sickness and other problems such as signal failures.
Aslef is also planning a week-long strike from January 9.
Mr Horton called for fresh talks at the conciliation service Acas to resolve the ongoing dispute.
Aslef general secretary Mick Whelan said drivers had been forced to strike because of the company's "intransigence".
He said: "We have tried everything possible this year to reach a sensible and workable compromise with Southern in the interests of passengers and management as well as of staff."