Rail travellers may face steeper fare rises in return for maintaining investment in the service, Transport Secretary Philip Hammond said on Thursday.
Hammond said the current formula for setting regulated rail fares could not be set in stone at a time when government budgets face huge cuts to rein in a record budget deficit.
"We will face some very stark choices and it would be irresponsible at this point to rule out even considering an increased contribution from the fare payer as part of the solution to protecting investment in the railways," Hammond said in a speech to an industry conference in Liverpool.
Regulated rail fares -- including season tickets for commuters -- are currently raised by 1 percentage point above the retail price index each year.
The RPI is currently running in excess of five percent, indicating that rail users face price rises of more than six percent even if the formula is maintained. The RPI figure for July is used as the basis for fare increases imposed from the following January.