Prime Minster David Cameron has promised better compensation to beleaguered passengers caught up in a dispute between Southern Railways and the rail union the RMT.
Mr Cameron branded the performance of company as "unacceptable" as a bitter dispute over the role of the conductor on the franchise continues.
Since April, four 24 hour strikes have taken place and levels of sickness among conductors and drivers at the company have risen, leading to cancellations of numerous services.
At Prime Minister's Questions Mr Cameron said: "Our transport infrastructure is a crucial part of our economy.
"I condemn any industrial action that disrupts the travelling public and rail passengers will not thank the RMT for their recent unnecessary disruption.
"Frankly the performance of Southern Rail has been unacceptable and passengers deserve better.
"I can tell the House that we will be providing more generous compensation to passengers affected by the latest strike and the transport secretary will be announcing further details soon."
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