Rail passengers will face average season ticket price rises of 3.5% in January following the announcement of the July inflation figures.

The new-year rises are based on the previous July's rate of Retail Price Index (RPI) inflation plus 1%.

With the Office for National Statistics announcing today that the RPI rate for July 2014 was 2.5%, commuters in England will have to fork out an average 3.5% extra in January unless the Government, decides, as it did for January 2014, to keep the rate to RPI plus 0%.

Train companies also have a "flex" rule which allows them to increase some regulated fares by 2% above the average as long the overall average remains at the RPI plus 1% level. This means some fares could go up by 5.5% in the new year.

The rise was condemned by Labour, with shadow transport secretary Mary Creagh saying: "David Cameron has failed to stand up for working people struggling with the cost-of-living crisis."

The TSSA transport union said Conservative ministers had to stop the annual "persecution of millions of rail passengers with inflation-busting increases".

And the Campaign for Better Transport pointed out that fares have gone up by more than 24% since 2010, while wages had only risen by 6.9% over the same period.

Rail Minister Claire Perry acknowledged that passengers had had to contend with "inflation-busting fare rises almost every year over the last decade" but insisted the Government was committed to "fair fares".

She said: "What we have got to do is make sure rail passengers, who could be forgiven for thinking 'What on earth am I getting for these rises I've seen over the last decade?', start to realise that they are paying fair fares for comfortable commuting."

Ms Creagh said: "David Cameron has allowed train companies to sting passengers with inflation-busting fare rises of over 20% since 2010, costing them hundreds of pounds.

"We can't go on like this. The choice facing passengers is between fares rising another 24% by 2018 under the Tories, or a Labour government which will cap annual fares on every route and enact the biggest railway reforms since the Tories' botched privatisation, delivering a better deal for passengers and taxpayers."

TSSA general secretary Manuel Cortes said "It is an absurd political myth that fares have to rise above inflation every year to pay for new lines. It is high time to stop this annual persecution of rail passengers."

David Sidebottom, director of rail customer watchdog Passenger Focus, said: "Many passengers will be concerned about today's news about the fare rise.

"This level of fare increase puts more pressure on the railways to ensure passengers get an excellent service for the money they are paying."

"We hope the Government will step in again as it did last year, to ensure that train fares in England do not rise above the rate of inflation announced today."

TUC general secretary Frances O'Grady said: "It's grim news for commuters that they face yet another year of fare hikes above inflation, while their wages keep dragging behind inflation. The cost to passengers of the failed privatisation of our railways keeps growing year on year."

Train drivers' union Aslef said rail privatisation had "left us with a fragmented system which is all about making a private profit at public expense", while the RMT transport union described the January 2105 rise as "a kick in the teeth" for passengers.