The nationalised company responsible for Britain’s rail infrastructure has insisted that it remains committed to improving train times between the region and London.

Network Rail said it was a keen member of the taskforce looking to improve journey times on the Great Eastern Main Line and was working to try to achieve the aim of running trains from London to Colchester in 40 minutes, Ipswich in 60 minutes and Norwich in 90 minutes.

The assurance comes after NR published its “Route Specifications Report 2015” which looked ahead to what services might be like in 2019 and 2043.

This said the journey times from London to Ipswich and Norwich would be the same in 2043 as they are today – however in its introduction it does point out that the information is subject to change later this year.

A spokeswoman for NR said it was currently carrying out a feasibility study looking into what infrastructure upgrades are necessary to achieve the aim of improved times and that should be completed in November.

She said: “The Great Eastern Main Line is a vital economic artery for East Anglia, connecting growing numbers of people and businesses in Essex, Suffolk and Norfolk with the capital.

“We have recently started a feasibility study. In the meantime, we will continue our work to deliver a better and more reliable railway, modernising track and overhead power lines on the line.”

The Route Specifications Report does suggest that the maximum speed on some sections of the line between Shenfield and Norwich could increase from 100mph to 110 mph by 2019 – and that by 2043 some sections of the Ipswich to Norwich line could carry trains running at 125mph.

Ipswich MP Ben Gummer welcomed the fact that Network Rail remained committed to the line improvements, and hoped that its departments would talk to each other to ensure there was no danger of misunderstandings.

He said: “I hope those in the planning departments of Network Rail will talk regularly to their route directors and regional managers who have been so helpful in the work we have been doing on the rail task force.”