Freezing fares for Southern passengers would "help to start rebuild trust" in the franchise, a rail passenger group has said.
Transport Focus urged Southern to freeze ticket prices after "months of misery they have experienced".
Passengers were beset by strikes and disruption for much of 2016 - and the misery will continue into this year, with another strike set to begin next Monday and lasting for almost a full week.
The plea from Transport Focus came as rail fares were expected to rise 2.3 per cent this year - higher than in the last two years.
"Many commuters, in London and the south east in particular, have suffered poor performance and will feel anger at paying more and getting less," said Anthony Smith, chief executive of Transport Focus.
The research, by Action for Rail, found commuters travelling the 35 miles from London to Luton spend an average of 14 per cent of their income on a monthly season ticket, compared with French passengers, who spend two per cent of their incomes, and German passengers, who spend three per cent.
The study also found UK train tickets have increased almost twice as fast as wages in the past 10 years.