It follows a probe by the Department for Transport (DfT). MP and transport select committee chairman Huw Merriman said he understood the Serious Fraud Office would investigate.

       The Government will now run Southeastern's network in London, Kent, East Sussex and the High Speed 1 line, from October 17. Transport Secretary Grant Shapps said: "There is clear, compelling and serious evidence that LSER have breached the trust that is absolutely fundamental to the success of our railways."

       Clare Hollingsworth, who chairs transport firm Go-Ahead, the majority owner of Southeastern's parent company Govia, said: "We recognise that mistakes have been made and we sincerely apologise to the DfT."