Southern Railway has one of the poorest levels of passenger trust in the country.
Southern, which operates along the coast from Portsmouth Harbour to Hastings, had the lowest overall rating from passengers across a range of areas.
On truthfulness, honesty and integrity and treating customers fairly, Southern was rated worse than any other operator, according to a Passenger Focus survey.
On principles, industry leadership and “doing the right thing when no one is looking”, Southern also scored worst.
A Southern spokeswoman said, “The report again draws the conclusion that there is a connection between performance and trust. Unfortunately the survey was completed in January – a time when our performance was severely affected by some of the worst weather in living memory.
“Since then we have been working hard with Network Rail to improve performance and have made some good progress recently with performance steadily improving month by month.
“We know there is still more to do to rebuild our passengers’ trust after what was a very long, frustrating winter for many of them.”
Anthony Smith, Passenger Focus’s chief executive, said, “There is much that train companies - and governments - can do to improve trust. It is important for train companies to get the basic service right ahead of everything else.
“Then building on closer relationships with their passengers is important. One way is through high quality communication. Passengers should feel that train companies are ‘on their side’. We believe these issues should become part of new franchises.”