EXTRA capacity cannot be delivered along the main line between Norwich and Liverpool Street without major infrastructure upgrades, a report has revealed.

During the next two years, rail services on this route are expected to be transformed through the replacement of the entire fleet with new, higher capacity trains.

Network Rail says a degree of extra capacity can also be delivered through re-timetabling to fit in extra services.

But over the next 25 years the demand for rail transport in the high peak hour towards London Liverpool Street is expected to grow between 40 and 60 per cent.

About 190 million journeys were made in 2017/18 within the East of England region compared to around 146 million in 2007/08, an increase of 30 per cent over 10 years.

Major improvements are needed along the route including between Marks Tey and Colchester.

Without these upgrades Network Rail has said that extra capacity cannot be delivered.

This position has worried campaigners fighting proposals for major housing developments along the route – especially at West Tey which could see 17,000-plus homes as part of the North Essex Garden Community plans.

Rosie Pearson, secretary of the Campaign Against Urban Sprawl in Essex, said: “We have been boring them to death for five years about rail capacity.

“It is definitely not adequate and we don’t think they should be building a new town on an overcrowded line without investment in it first.”

A Network Rail spokesman said: “Our study sought to identify the expected growth on the Great Eastern Main Line over the next 25 years, additional services that might be needed and various infrastructural schemes required to run these.

“They include creating train passing lines (“loops”) between Chelmsford/Witham and south of Colchester.

“We are still prioritising these schemes and conducting detailed timetable assessments that will allow public and private sector funders to make informed planning decisions.

“We are also developing the strategy in consultation with local councils and acknowledging the rising demands for housing in the area.”