A July inflation figure on which annual rail fare rises have historically been based was 3.6% this year, the Office for National Statistics announced.
That was last month’s Retail Prices Index (RPI), which until 2023 was used by Westminster governments to set the cap on annual increases in regulated fares in England.
The Department for Transport (DfT) has not revealed whether this will be used to determine changes in the cost of train travel.
The rise in fares in 2023 was based on the UK’s average earnings growth during the quarter to July 2022, while a figure of 4.9% – not believed to be linked to any specific economic measure – was used for the 2024 increase.
About 45% of fares on Britain’s railways are regulated by the Westminster, Scottish and Welsh Governments.
They include season tickets on most commuter journeys, some off-peak return tickets on long-distance routes, and flexible tickets for travel around major cities.
Train operators set rises in unregulated fares, although these are likely to be very close to changes in regulated ticket prices because the companies’ decisions are heavily influenced by governments due to contracts introduced because of the coronavirus pandemic.
A DfT spokesman said: “The Transport Secretary is delivering the biggest overhaul of our railways in a generation, to provide better services for passengers, while saving millions of pounds in fees paid to the private sector.
“No decisions have been made on next year’s rail fares but our aim is that prices are as affordable as possible for passengers.”
The Government is planning to announce fare rises later this year.
It has promised to bring all passenger railway services back into public ownership when existing private contracts come to an end and has introduced the Passenger Railway Services (Public Ownership) Bill to achieve this.
Chris Page, who chairs lobby group Railfuture, said: “When the UK, Welsh and Scottish Governments decide how much to bump up fares next year, we want to see decisions that are fair for passengers.
“The acid tests will be how the increases compare with costs paid by other modes of travel, most noticeably coaches, air and, of course, the car.
“Domestic British air travellers are paying just over half the previous rate for air passenger duty, and vehicle fuel duty has not increased since 2011.
“But since 2011 British rail fares have risen by over 50%.”
Johnbosco Nwogbo, lead campaigner at anti-privatisation group We Own It, said: “After 30 years of ever-increasing fares in exchange for endless cancellations and a shoddy service, the Government has now set our railway on the right track.
“But rail nationalisation must also bring real change on fares.
“British passengers pay some of the highest fares in Europe.
“With the reforms the Government is introducing to the railway, they have a historic opportunity to create a rail fares policy that puts passengers and planet first.
“With temperatures hitting historic highs, our railway can be a lever in the fight against climate change by luring drivers back to the trains.”