Train fares could rise by as much as 5.6 per cent next year - meaning some commuters in the Home Counties will have to pay more than £5,000 to get to work.
Rail passengers will learn on Tuesday how much season tickets will rise in January 2015, with transport campaigners saying fares are increasing four times faster than wages.
The Retail Prices Index inflation figure for July 2014 will be published on Tuesday and will be used as a base for January 2015 prices.
According to the Daily Telegraph, fares are expected to rise by around 3.6 per cent if the July figure is similar to that of June, but in some cases they could see a 5.6 per cent increase.
A 3.6 per cent rise would mean commuters travelling from Ashford, Kent to London would pay £5,105 a year.
Workers from Milton Keys would pay £4,943 to get to London, while those travelling from Portsmouth would pay £4,964.
According to the Daily Mail, the Campaign for Better Transport (CBT) says that fare changes are calculated by a "discredited measurement. The RPI is deemed to over-estimate inflation."
CBT added: "Our research has shown that the Government's practice of linking regulated fares to RPI rather than the more accurate CPI measure has cost commuters hundreds of pounds over the last decade."
The Department of Transport said: "No decisions on fare rises for 2015 have yet been taken."
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