Train fares are to rise by an average of 8 per cent in the new year.
Commuters from Brighton, Hove and Portslade to London are likely to be paying at least £250 a year more.
The new price of a season ticket will be about £3,200.
The price rises are linked to the July inflation figures, in particular, the retail prices index (RPI).
Under a three-year deal, regulated fares such as season tickets are rising at RPI plus 3 per cent and the crucial July RPI figure was 5 per cent.
For many years rail fares rose by RPI minus 1 per cent.
The rises are part of the Conservative and Liberal Democrat coalition government’s agenda to reduce the cost to the taxpayer of running the rail network.
Shelley Atlas, of Brighton Line Commuters, said: “Passengers are very concerned about these fare rises and I have been asked by several passengers if the percentage they are quoting is actually correct.
“Their concern is understandable, with redundancies and pay freezes and those out of work hoping to secure new jobs.
“There is also a concern for young people starting out on their careers – they are mostly on new starter’s salaries and they will find it even more difficult to pay these higher fares.”
She added that the fare rises would also have an impact on shops and other businesses in places such as Brighton with fewer holidaymakers and day trippers willing to pay the higher fares.