Train passengers are expected to see fares rise by more than 3% again next year.

The rise will be confirmed when the Office of National Statistics sets the latest Retail Price Index inflation figure this week.

Leading economics experts have warned it could be as high as 3.5%.

The cap on the level of annual increase train operators can charge is linked to the inflation figure. The RPI for July is used for fares rises the following January.

Regulated fares include season tickets on most commuter routes, some off-peak return tickets on long distance journeys and Anytime tickets around major cities.

These fares went up by 3.6% this year.

Rail unions and passenger groups called for a freeze when the new fares are set this coming January.

A Campaign for Better Transport spokesman, said: “Given the mess surrounding the new timetable, the lack of improvements and the failure to deliver compensation, the Government cannot go on telling passengers that fare increases are justified.”

Passenger group have called for the RPI benchmark to be replaced with the Consumer Price Index which is generally lower. which the governor of the Bank of England said was more relevant.

Mick Cash, general secretary of the Rail, Maritime and Transport union, said: “This is another kick in the teeth for Britain’s passengers who are being robbed blind by greedy train operators for travelling in rammed out and unreliable services while the shareholders are laughing all the way to the bank.

Manuel Cortes, general secretary of the Transport Salaried Staffs’ Association, said: “Justice for passengers means dropping the annual rip-off rise and also simplifying the Byzantine fare structure which privatisation has imposed.

“Better still, end this costly farce. Put passengers before profits by bringing our railways back into public ownership.”

In Scotland the cap is lower so the increase could be lower than average across the UK.

A Scottish Government spokesman said: “ScotRail’s fares increases are generally lower, on average, than those elsewhere in the UK.

“This is a result of our policy to place a cap that is lower than RPI on regulated off-peak fares increases, whereas the UK Government applies an increase at the level of RPI to all regulated fares.”