The case for long-awaited rail improvements will be presented to ministers next year.

MPs and business leaders will set out the case for the work to be carried out at Ely North junction, where lines from all four corners of the region meet.

The work was originally due to be carried out between 2009 - 14, but it was rescheduled in a spending review.

South West Norfolk MP Elizabeth Truss hosted a summit meeting in Ely yesterday to review progress on the junction.

She said the scheme would bring 'great economic benefit', adding: 'I'm committed to making sure this is constantly at the top of the government's agenda.'

Ms Truss said the estimate that the improvements would bring an extra £1bn to the region's economy each year were 'a vast underestimate'.

Studies looking at how the work might be carried out are now under way.

Improvements would cut delays and allow more trains to run on the King's Lynn to London and Norwich to Cambridge lines, cutting crowding.

But the meeting heard a road bridge or underpass would now be needed to ease congestion in Queen Adelaide, where there are three level crossings on half a mile of road.

Vehicle numbers through the village are forecast to increase from 4,800 to 8,000 a day once thousands of new homes planned for land around Ely are built.

The government will be lobbied to fund both rail and road schemes. A business case will be submitted in April.

Mid Norfolk MP George Freeman said Ely North was a 'blocked artery' which strangled economic growth.

James Palmer, mayor of Cambridgeshire and Peterborough, said Cambridge's economy would begin falling behind other world-leading cities without the investment.

Design work on extended platforms at Littleport and Waterbeach is now under way.

Meliha Duymaz, Network Rail's route managing director for Anglia, said once completed, the extensions would enable eight-carriage trains to run between King's Lynn and Cambridge, easing over-crowding.

The longer trains were originally due to enter service this year. Ms Duymaz said the improvements would now be completed 'as early as possible in 2019'.