Southern has been voted as the worst train service in the UK for the third year in a row.
The consumer group Which found only 28% of those asked were satisfied with the rail operator.
It scored badly on value for money, reliability and punctuality, with 37% saying the service had got worse in the last year.
For nearly two years now the company owned by Govia Thameslink has been embroiled in a dispute with the RMT over driver-only trains. Southern says the Which report fails to take this complex situation into account.