The new Conservative government has announced a delay in the modernisation of the UK's rail network.

Despite unveiling a series of upgrade programmes that would bring the country's railways into the 21st century in its election campaigning, the government has conceded that the plans are now untenable in their current format. The north of England will bear the brunt of the changes with key routes being shelved.

Improvements to the TransPennine line between York and Manchester have been shelved, as has the Midland main line between York and Sheffield. Cities such as Derby, Nottingham and Leicester will have to wait for improved services to London as the government believes the Great Western main line between London and Cardiff is more of a priority.

Transport secretary Patrick McLoughlin confirmed that rising costs and missed targets were the reasons why the £38.5 billion plan has become untenable. Commentators have explained that this decision will mean that the improvements will now take longer to be brought to fruition and ultimately cost more.

The move has generated major criticism from opposition parties. While Network Rail said the plan would be the "largest modernisation of the railways since Victorian time" it has turned out to be too ambitious, Labour sees it as an example of the Conservatives breaking election promises.

Michael Dugher, shadow transport secretary, said: "We have been warning time and time again there needs to be fundamental changes in how our railways are run. You spent the election campaign repeating promises you knew you would break after the election.

"Ministers may try to shift all the blame to Network Rail, but this happened on the government's watch and the responsibility for this mess lies squarely with the government."

In the run-up to the election, the state of the UK's rail network was a major focus for many of the parties with all of them in agreement that work needed to be done to upgrade the current system. A series of electrification programmes were laid out while chancellor George Osborne stressed the need to create a 'Northern Powerhouse'.

This would require much improved rail links and slash the journey times between a number of the major cities in the north of England. There have also been discussions about rolling out the much-criticised HS2 programme to cities like Leeds and Manchester, and then Newcastle in a bid to connect the north with London.

Alongside the delay for the improvement work, figures from Transport Focus highlighted that satisfaction in the nation's rail networks had been falling in the past 12 months. Passengers in London and the south-east of England were the least happy with the service while the overall satisfaction had fallen from 82 per cent to 80 per cent in the space of a year.

First Hull Trains recorded the highest satisfaction rate at 96 per cent while Southern was bottom of the pile with just 72 per cent.

Commenting on the figures, Transport Focus chief executive, Anthony Smith said: "Commuters will not be surprised at these results. Long-term plans and investment are important and welcome – how the work is carried out, though, is crucial."