Transport secretary Chris Grayling will decide within two weeks if the Southern rail franchise is in breach of its contract, as the High Court today threw out an application from a commuter group to force a judicial review into the matter.
The Association of British Commuters was seeking a solution on Grayling's handling of the embattled rail franchise.
The Department for Transport (DfT) claimed victory yesterday and said: "We are pleased the High Court has thrown out the application for a judicial review by the Association of British Commuters.
"An independent report by rail expert Chris Gibb, which was published last week, made it very clear that the responsibility for disruption on Southern was primarily caused by industrial action led by RMT and Aslef and exceptional levels of staff sick leave."
A spokesperson said the department will "imminently" rule on Southern's franchise obligations throughout the industrial dispute but there will not be a further report into the matter.
"We have been considering whether the extensive disruption to the line last year was entirely beyond [franchise owner] GTR's control and our decision was due to be communicated to the company imminently.
"We are more than happy to inform GTR of the verdict within the 14 days required by the judge."
The commuters' group tweeted that today's decision was "complicated" but "a precedent has been set for public interest in private contracts".
"We can tolerate no more cover ups on Southern rail."
Commuters have been hit by more strike action today as unions continued to fight with Southern over the role of the guard.
Southern is attempting to roll out driver-only trains, which the unions have argued are unsafe.
The service was forced to operate with only a quarter of its trains today, affecting commuters in Kent, Sussex, Surrey and Hampshire.
Direct services between London and Southampton and London and Portsmouth have been cut, and there is only a limited service between Gatwick and Brighton.