Congestion on the region's road could cost people and businesses £2bn a year by 2021 - double the present levels - unless radical action is taken to ease gridlock.

Congestion on the region's road could cost people and businesses £2bn a year by 2021 - double the present levels - unless radical action is taken to ease gridlock.

That is the verdict of a study by the East of England Development Agency (Eeda) launched at a regional transport summit in Newmarket yesterday.

The report, the first of its kind in the UK, identifies a number of congestion corridors that should be tackled to keep the region moving.

It says the focus should be concentrated on trouble-spots close to London and Cambridge.

And it suggests improving rail services between the capital and Norwich by introducing longer trains out of Liverpool Street and upgrading the line.

This, the study team says, would have a greater return in terms of boosting productivity than any other route in the region because of the city's strength as a financial sector.

The study attempts to calculate the losses in productivity caused by delays to businesses and individuals and estimates that 85pc of the costs of congestion are borne in the region's seven “engines of growth”, including Norwich.

It also makes a series of assumptions by 2021 including:

Dualling of the A11 between Thetford and Fiveways roundabout at Barton Mills.

Dualling of the the A47 between Blofield and North Burlingham.

Completion of the proposed Norwich northern bypass.

Richard Ellis, chairman of Eeda, said the study provided the economic evidence to support the region's case for continued investment in the transport network.

“The study is important, not just in the region but nationally as well, because the East of England is one of only three regional net contributors to UK plc,” he said.

“Maintained investment in the region's transport network is, therefore, vital to the national economy and to help businesses compete in a global market place.

“Investment in transport is critical to supporting the regional and national economy, but, equally, working smarter and managing demand will be key to unlocking economic growth. It now time for all of us to get behind our regional transport campaign to lobby for a more reliable, effective and safer transport network for benefit of all who live, work and invest in the East of England.”

Barbara Follett, minister for the East of England, said there was a need to develop and implement more innovative approaches, such as opening the hard shoulder on motorways when traffic was at its heaviest, alongside some conventional road widening where that made best sense.

“We need to be smart about new investment in our infrastructure, and I look forward to passing on some good ideas and suggestions that arise from our work here today,” she said.

Richard Bindless, director of the East of England Business Group, said: “For years, transport infra-structure inadequacies have held back this region's economy, damaging the competitiveness and profitability of our company base.

“This study provides a sound basis for targeting investment to greatest effect and also provides a strong rationale for addressing the problem of congestion in new ways.”