Level crossings in Norfolk and Cambridgeshire towns and villages are to be shut to allow twice-hourly train services to run between King's Lynn and London.

The latest hurdle to the 'critically important' more frequent service has emerged as council leaders said Network Rail had confirmed to them that there would be a year-long delay in a vital upgrade to the Ely Junction.

It is not yet clear which crossings would close, and Network Rail said work is ongoing. Council bosses have spoken of their disappointment after they were told the long-awaited rail upgrade in Ely –which is also key to a more regular service - will be delayed by a year to 2018.

Rail building body Network Rail announced after the General Election that it would be putting northern electrification schemes on pause, and it would be reviewing all of its major projects, including the Ely North junction.

But it said the upgrade of Ely North Junction remained one its commitments before 2019.

A spokesman added: 'To run additional services between King's Lynn and Cambridge, we need to upgrade the junction and also to consider the impact on level crossings on the King's Lynn line, and this work is ongoing.'

Brian Long, cabinet member for the environment at West Norfolk District Council, said: 'To learn that the work to complete the Ely North Junction will not be complete until autumn 2018 instead of autumn 2017 is disappointing to say the least.

'Having met with Network Rail we are also advised that work is required to the level crossings to enable this service to happen – something that wasn't previously made clear to us.

'We have long been pushing for a half-hourly train service between King's Lynn and London as we see this as vital to the future economic growth of the town.

'We will continue to work with our local MPs, Norfolk and Cambridge county councils and the New Anglia and Greater Cambridge Greater Peterborough Local Enterprise Partnerships to press for the timely delivery of the promised half-hourly service.

'We will also look at the potential for operating an eight-car train service at peak times rather than the current four-car service and will be lobbying for a study to be carried out to ascertain what work is needed on the level crossings.'

Chris Starkie, managing director of New Anglia Lep said.' This is a critically important junction for rail services across East Anglia. We will continue to press Network Rail to make the improvements as quickly as possible and we are also campaigning for the introduction of longer trains to ease congestion on the Kings Lynn to London route.'

There are currently 6,300 level crossings across the UK. Network Rail has a national policy to close crossings where an agreement can be reached. It said that it is rolling out red light safety cameras, power operated gates and it aims to close at least another 250 crossings nationally.

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