Transport bosses in West Yorkshire are locked in talks with the government to avert a crippling 10 per cent rail fare hike next year.
Commuters travelling into Leeds face being hit by the biggest percentage increase in their season tickets anywhere in the country under an obscure funding agreement hammered out four years ago.
It has emerged that - assuming inflation stays at its current level - the 840 annual rail fare from Wakefield, Bradford, Castleford or Dewsbury into Leeds is to soar by 84 to 924 next year.
Similarly, the season ticket from Huddersfield to Leeds is to jump by 124 to 1,236, while the ticket from Halifax to Leeds could increase by 98 to 1,086.
These increases will be 2 per cent higher than anywhere else in the country.
Currently, regulated fare increases - everywhere other than West Yorkshire - are capped at the RPI measure of inflation, which is 4.8 per cent, plus an additional one per cent on top.
However, in West Yorkshire fares are capped at RPI inflation plus three per cent.
This is because of a deal agreed between transport authority Metro and the government to lease six additional two carriage trains, at a cost of 20m, to ease overcrowding on some of the region's busiest rail routes.
The extra trains, which provide more than 800 additional seats at peak times, were to be partly paid for by a higher cap on regulated fares, which includes season tickets and saver fares.
Following Chancellor George Osborne's Comprehensive Spending Review, regulated rail fares will next year increase elsewhere in the country by RPI plus 3 per cent.
But in West Yorkshire, the hike is set to be RPI plus 5 per cent. If inflation remains at its current level, it means that tickets are set to increase by an eye-watering 10 per cent.
Metro spokesman said: "Metro and Northern are in discussion with the Department for Transport at the moment about ways in which this situation can be mitigated, but no decisions have been made yet. The discussions are at a very early stage."
He added: "Many of the additional carriages introduced five years ago are now full to standing again."
Leeds West Labour MP Rachel Reeves said: "At a time when families across West Yorkshire are having to tighten their belts with cuts, VAT increases and petrol price rises, this is the last thing that people want."
A Department for Transport spokesman said: "The scale of the deficit means that the Government has had to take tough decisions on future rail fares.
"No decision on how rail fares will be change in West Yorkshire has been made and we will discuss with relevant PTEs how the national policy will be reflected in their regions."