The Mayor of London, Sadiq Khan, has called for the government to strip Southern of its rail franchise, after weeks of problems and commuter fury.
Khan said he was "appalled at the unceasing misery being inflicted on tens of thousands of passengers", and asked the Department of Transport to take temporary responsibility for the operating of the line, from Govia Thameslink, the current holder.
He also said the suburban rail services should be transferred to Transport for London (TfL) as soon as possible.
"Passengers are paying thousands of pounds for a service that rather than being 'turn up and go' has become 'turn up and hope'," says Khan. "Their frustration at such a disgraceful level of service is obvious and it is justified.
"This utter mess is now an embarrassment to our city, it is an insult to hard-working Londoners who pay their fares and it must be fixed.
"Ministers need to put in place a new and faster timetable for handing over inner suburban rail services to Transport for London, so that we can provide passengers with the improved services, stations and fares they deserve."
Weeks of industrial action and "unprecedented levels of staff sickness" have caused misery for commuters, compounded by Southern cutting 341 trains from its timetable.