The government has taken over rail operator Southeastern of its franchise after “a serious breach of good faith”.
Transport Secretary Grant Shapps said more than £25m of historic payments due to the Department for Transport were not declared.
In a series of tweets, Shapps said: “We won’t accept anything less from the private sector than a total commitment to their passengers, and transparency with taxpayers.
“Through the Operator of Last Resort we’ll prioritise the punctual, reliable services passengers deserve.”
Southeastern, that operates services between London, Kent and East Sussex, will not change fares and services.