Britain's train passengers could be hit by the largest fares rise in a decade.

       Increases are usually linked to the previous July's Retail Prices Index (RPI) measure of inflation, which was confirmed as 3.8 per cent for July 2021 by the Office for National Statistics on Wednesday.

       No announcement has been made on what will happen to fares next year, but ticket prices in England and Wales rose by an average of around 2.6pc in March, representing RPI for July 2020 plus one percentage point.

       The Scottish Government imposed smaller rises of 1.6pc and 0.6pc for peak and off-peak travel respectively.

       A repeat of the policy in England and Wales next year would see fares rise by an average of 4.8pc, which would be the largest increase since 2012.

       That is the amount that public transport fares in London are set to be hiked by in January, under the terms of the UK Government's bailout of Transport for London.

       Rises in fares for mainline rail services across Britain are controlled by the UK, Scottish and Welsh governments.

       A spokesman for the UK Government's Department for Transport said: "No decision has been made on national rail fares.

       "The Government is considering a variety of options and we will announce our decision in due course."

       Rail fares are usually increased every January, but the coronavirus pandemic meant this year's increase was delayed until March 1.

       Emma Gibson, director of passenger watchdog London TravelWatch, said: "Fares in London need to be affordable if people are to be tempted back to public transport and out of their cars.

       "Many Londoners have already suffered financially as a result of the pandemic so a 4.8pc fares increase is the last thing they will want to see."

       Fares for rail services in Northern Ireland are set by state-owned operator Translink, which does not use RPI.