RAIL commuters are being warned to expect a fare increase of up to 3.5% next year.

This would increase the annual cost of getting to and from work by more than £150 for many long-distance travellers .

The exact fare rise will be confirmed when the July Retail Prices Index (RPI) measure of inflation is released by the Office for National Statistics on Wednesday.

The changes are unlikely to affect commuters in Scotland though, due to a difference in the way fares are calculated.

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

Last year, the average fare in Scotland increased by 3.2% while the rest of the UK saw prices go up by 3.4%.

He added: “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.”

Westminster’s Department for Transport (DfT) uses July’s RPI to determine the annual increase in regulated train fares, which comes into force every January.

The governor of the Bank of England, Mark Carney, has said RPI has “no merit”, adding that “virtually everyone recognises” the alternative Consumer Prices Index (CPI).

Rail campaigners want CPI to be used to determine regulated fare increases, as it is generally lower than RPI.

The introduction of a new timetable caused widespread chaos in the north of England and on various London commuter lines.

Thousands of passengers are still waiting to receive enhanced compensation after Great Northern, Thameslink, Southern and other services were cancelled or delayed after the launch.

Some services have been partially resumed however problems have continued. Yesterday around 80 Northern rail services were cancelled, affecting passengers across Liverpool, Greater Manchester and Lancashire.

The timetable disruption has led to the Government vetoing further changes expected in December, which means upgrades in areas such as the West Midlands and South Western Railway routes have been cancelled or delayed indefinitely.

A Campaign for Better Transport spokesman urged the Government to “commit to a fares freeze”.

He 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.”

Manuel Cortes, general secretary of the Transport Salaried Staffs’ Association, said services are in “free fall”.

He continued: “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.”

A DfT spokesman said: “Any fare increase is unwelcome, but it is not fair to ask people who do not use trains to pay more for those who do.

He added: “Taxpayers already subsidise the network by more than £4 billion a year – meaning that 38% of our transport budget is spent on the 2% of journeys that the railway accounts for.”