Commuters on Northern Rail are facing rail fare hikes of up to 117 per cent from today following the axing of off-peak fares.
The price rises - which affect many evening services run by the Northern Rail train company - have been criticised by rail unions and campaign groups.
The Campaign for Better Transport (CBT) said the changes would particularly hit part-time and shift workers.
Examples of the increases being introduced today include:
* Wigan to Manchester Piccadilly return rises from £4.20 to £9.10 (up 117 per cent).
* Hexham to Newcastle return rises from £3.55 to £7.10 (up 100 per cent).
* Bradford to Leeds return rises from £4.70 to £6.50 (up 38.3 per cent).
CBT public transport campaigner Martin Abrams said: "This fare increase threatens to make rail travel unaffordable to tens of thousands of part-time workers.
The increases come into effect just a day after Chancellor George Osborne announced that he was knocking one per cent off the January 2015 national commuter fare rise for England.
This means that regulated fares, which include season tickets, will be going up by 2.5 per cent rather than the planned 3.5 per cent.
The RMT union says the rises are "a kick in the teeth for the travelling public" and a "taste of what's around the corner under the new franchises".
"Despite Government promises, there are no flexible tickets for the increasing numbers who work part time or anything other than traditional nine-to-five hours.
"Their only option is to pay for individual tickets, which will now be double the price on Northern Rail's most popular routes."
RMT acting general secretary Mick Cash said: "The axing of off-peak fares is a savage kick in the teeth for people already struggling with the burden of low pay and austerity."
Northern said the fare changes were being made after the Department for Transport asked the company to look at several options to help reduce subsidy as part of its current franchise agreement.
The company said it had heavily publicised the fare changes.
Northern Rail commercial director Richard Allan said: "The majority of customers who travel at peak times will be unaffected by these changes but we want to make sure that those who are know about what is happening and what options are available to them."
Shadow transport secretary Mary Creagh said: "Rail fares normally go up in January but commuters in George Osborne and Nick Clegg's constituencies face stealth fare hikes of up to 52% this September.
"This is a direct result of the Government's West Coast franchise fiasco and commuters travelling to Leeds, Manchester, Bradford, Sheffield and Newcastle are paying the price."
She went on: "People shouldn't have to choose between paying more or waiting until after dark to travel. Commuting looks very different when you're travelling in the back seat of a Government car.
"Labour would tackle the cost-of-living crisis by enforcing a strict cap on fare rises and reforming our railways for passengers, not profit."
A Department for Transport spokesman said the changes would help build a "rail network that is better for the passenger and better value for the taxpayer".
"Such restrictions are relatively common on other parts of the network, including in the Mersey travel area, and we expect only a minority of passengers to be affected," he added.
Northern Rail disputed one of the CBT figures. Northern Rail said the Hexham to Newcastle fare was rising from £7.10 to £7.90, representing an increase of 11%.
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