Update: 5.40pm, 6 January 2015: Following an MoneySavingExpert investigation we've updated this story, you can read the new version here: Promises of cheaper self-service rail tickets overblown

Commuters will be told about the cheapest train fares available for their journey from March as part of a new rail fare code of conduct.

Reforms will be introduced to stop customers paying over the odds for journeys bought via self-service machines when cheaper options are available. (See MoneySavingExpert.com's Cheap train tickets guide to find hidden fares and split tickets).

Currently, staff at counters have access to a complex database of fares, discounts and promotions, so customers have more options and often pay less for the same journey than when buying tickets from ticket machines.

The move follows an investigation by The Daily Telegraph which found that some machines promoted expensive fares, bury cheap options and do not apply discounts for groups or families, leading to a difference in ticket prices of up to £100.

As part of a rail fare code of conduct, which will be overseen by the Office of Rail Regulation, train companies will be expected to overhaul their systems to ensure that customers are automatically offered all available ticket options.

As a first step, they must label all self-service machines by March to warn passengers they could save money by using the counter service.

'Passengers should get the best possible deal for every journey'

Rail minister Claire Perry says: "I am absolutely determined that passengers should get the best possible deal for every journey.

"There is no excuse for poor-quality information, restricted ticket choice or confusing screen directions at ticket machines.

"I welcome the fact that the industry has responded to the challenge with some positive actions which will be rolled out by next March.

"However, one summit is not the end of our discussions. I will be closely monitoring progress and I will not hesitate to hold the industry to account if improvements are not made."

Today, the price of season tickets, including London Travelcards, has risen by up to 2.5% (based on July's RPI rate of inflation), with the average price increase at 2.2% for commuters in England, Wales and Scotland.