The Department for Transport is reportedly considering seizing control of the controversial rail franchise including Southern Rail as one of a range of options to improve service.
A report from Rail Business Intelligence magazine had suggested that Whitehall officials were preparing a number of plans, including splitting off Southern from Govia Thameslink Railway, as well as taking direct control over the entire franchise.
The DfT reportedly began to explore the plans as a result of GTR's failure to hit operational targets, including numbers of services running on time.
Ministers offered up £20m in September in a bid to help improve Southern services, acknowledging that passengers had faced “unacceptable” disruption.
A DfT spokesman confirmed that GTR had made a “force majeure” claim to the government, in which it had claimed that cancellations were down to official and unofficial industrial action.
“There are no plans to strip GTR of the franchise. We monitor the operational and contractual performance of all franchises,” the spokesman said.
“Analysis of the force majeure is complex and therefore takes some time to properly assess. We continue to analyse GTR's claims while keeping performance and costs under review.”
RMT general secretary Mick Cash said: “Instead of dragging this farce out any longer the government should now do the decent thing, pull the plug on the GTR contract, take the lines under public control and draw a line under this shambles that shames Britain’s railways.
“As part of that process they should get round the table with the union and reach a genuine and lasting negotiated settlement to the on-going guards safety dispute.”
A GTR spokeswoman said: "The franchise contract is awarded by the government, and so it is for them to comment."